Competive Exam Math 2

Q. A bag contains ₹1 and ₹2 coins. The total number of coins is 10, and their total value is ₹16. What is the difference between the number of ₹2 coins and ₹1 coins ? (āĻāĻŸāĻž āĻŦā§‡āĻ—āĻ¤ ₹ā§§ āĻ†ā§°ā§ ₹ā§¨ āĻŸāĻ•āĻžā§° āĻŽā§āĻĻā§ā§°āĻž āĻ†āĻ›ā§‡āĨ¤ āĻŽā§āĻ  āĻŽā§āĻĻā§ā§°āĻžā§° āĻ¸āĻ‚āĻ–ā§āĻ¯āĻž ā§§ā§ĻāĻŸāĻž āĻ†ā§°ā§ āĻ¸āĻŋāĻšāĻāĻ¤ā§° āĻŽā§āĻ  āĻŽā§‚āĻ˛ā§āĻ¯ ₹ā§§ā§ŦāĨ¤ ₹ā§¨ āĻŸāĻ•āĻžā§° āĻŽā§āĻĻā§ā§°āĻž āĻ†ā§°ā§ ₹ā§§ āĻŸāĻ•āĻžā§° āĻŽā§āĻĻā§ā§°āĻžā§° āĻ¸āĻ‚āĻ–ā§āĻ¯āĻžā§° āĻŽāĻžāĻœāĻ¤ āĻĒāĻžā§°ā§āĻĨāĻ•ā§āĻ¯ āĻ•āĻŋāĻŽāĻžāĻ¨ ?)  Options / āĻŦāĻŋāĻ•āĻ˛ā§āĻĒāĻ¸āĻŽā§‚āĻš: A. 3  B. 1   C. 4   D. 2


Soln


Let (āĻ§ā§°āĻŋ āĻ˛āĻ“āĻ), x = Number of ₹1 coins (₹ā§§ āĻŸāĻ•āĻžā§° āĻŽā§āĻĻā§ā§°āĻžā§° āĻ¸āĻ‚āĻ–ā§āĻ¯āĻž), y = Number of ₹2 coins (₹ā§¨ āĻŸāĻ•āĻžā§° āĻŽā§āĻĻā§ā§°āĻžā§° āĻ¸āĻ‚āĻ–ā§āĻ¯āĻž)


Given (āĻĻāĻŋāĻ¯āĻŧāĻž āĻ†āĻ›ā§‡): Total coins = 10 (āĻŽā§āĻ  āĻŽā§āĻĻā§ā§°āĻž = ā§§ā§Ļ) : x + y = 10, Total value = ₹16 (āĻŽā§āĻ  āĻŽā§‚āĻ˛ā§āĻ¯ = ₹ā§§ā§Ŧ) : x +2 y = 16


Subtract the first equation from the second. (āĻĒā§ā§°āĻĨāĻŽ āĻ¸āĻŽā§€āĻ•ā§°āĻŖāĻŸā§‹ āĻĻā§āĻŦāĻŋāĻ¤ā§€āĻ¯āĻŧāĻŸā§‹ā§° āĻĒā§°āĻž āĻŦāĻŋāĻ¯āĻŧā§‹āĻ— āĻ•ā§°ā§‹āĻāĨ¤)


(x + 2y) − (x + y) = 16 − 10 = 6, 


Now (āĻāĻ¤āĻŋāĻ¯āĻŧāĻž), x = 10 − 6 = 4


Therefore (āĻ¸ā§‡āĻ¯āĻŧā§‡), â‚š2 coins = 6 (₹ā§¨ āĻŸāĻ•āĻžā§° āĻŽā§āĻĻā§ā§°āĻž = ā§ŦāĻŸāĻž), ₹1 coins = 4 (₹ā§§ āĻŸāĻ•āĻžā§° āĻŽā§āĻĻā§ā§°āĻž = ā§ĒāĻŸāĻž)


Difference (āĻĒāĻžāĻ°ā§āĻĨāĻ•ā§āĻ¯): 6 − 4 = 2


Ans(āĻ‰āĻ¤ā§āĻ¤ā§°): D. 2


Short Trick


Since every coin is assumed to be ₹1 at first: 10 coins = ₹10 (if all were ₹1 coins), Actual value = ₹16


Extra value = ₹16 − ₹10 = ₹6


Each ₹2 coin adds ₹1 extra compared to a ₹1 coin.


So, Number of ₹2 coins = Extra value = 6


Then, Number of ₹1 coins = 10 − 6 = 4


Difference (āĻĒāĻžāĻ°ā§āĻĨāĻ•ā§āĻ¯): 6 − 4 = 2


Ans: D. 2


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Practice Set


Q1. A bag contains ₹1 and ₹2 coins. The total number of coins is 12 and their total value is ₹19. What is the difference between the number of ₹2 coins and ₹1 coins ? (āĻāĻŸāĻž āĻŦā§‡āĻ—āĻ¤ ₹ā§§ āĻ†ā§°ā§ ₹ā§¨ āĻŸāĻ•āĻžā§° āĻŽā§āĻĻā§ā§°āĻž āĻ†āĻ›ā§‡āĨ¤ āĻŽā§āĻ  āĻŽā§āĻĻā§ā§°āĻž ā§§ā§¨āĻŸāĻž āĻ†ā§°ā§ āĻŽā§āĻ  āĻŽā§‚āĻ˛ā§āĻ¯ ₹ā§§ā§¯āĨ¤ āĻĒāĻžā§°ā§āĻĨāĻ•ā§āĻ¯ āĻ•āĻŋāĻŽāĻžāĻ¨ ?) Options / āĻŦāĻŋāĻ•āĻ˛ā§āĻĒāĻ¸āĻŽā§‚āĻš: A. 2  B. 3  C. 5  D. 7


Q2. A bag contains ₹1 and ₹2 coins. The total number of coins is 15 and their total value is ₹23. What is the difference between the number of ₹2 coins and ₹1 coins ? (āĻāĻŸāĻž āĻŦā§‡āĻ—āĻ¤ ₹ā§§ āĻ†ā§°ā§ ₹ā§¨ āĻŸāĻ•āĻžā§° āĻŽā§āĻĻā§ā§°āĻž āĻ†āĻ›ā§‡āĨ¤ āĻŽā§āĻ  āĻŽā§āĻĻā§ā§°āĻž ā§§ā§ĢāĻŸāĻž āĻ†ā§°ā§ āĻŽā§āĻ  āĻŽā§‚āĻ˛ā§āĻ¯ ₹ā§¨ā§ŠāĨ¤ āĻĒāĻžā§°ā§āĻĨāĻ•ā§āĻ¯ āĻ•āĻŋāĻŽāĻžāĻ¨ ?) Options / āĻŦāĻŋāĻ•āĻ˛ā§āĻĒāĻ¸āĻŽā§‚āĻš: A. 1  B. 3  C. 7  D. 9


Q3. A bag contains ₹1 and ₹2 coins. The total number of coins is 20 and their total value is ₹32. What is the difference between the number of ₹2 coins and ₹1 coins ? (āĻāĻŸāĻž āĻŦā§‡āĻ—āĻ¤ ₹ā§§ āĻ†ā§°ā§ ₹ā§¨ āĻŸāĻ•āĻžā§° āĻŽā§āĻĻā§ā§°āĻž āĻ†āĻ›ā§‡āĨ¤ āĻŽā§āĻ  āĻŽā§āĻĻā§ā§°āĻž ā§¨ā§ĻāĻŸāĻž āĻ†ā§°ā§ āĻŽā§āĻ  āĻŽā§‚āĻ˛ā§āĻ¯ ₹ā§Šā§¨āĨ¤ āĻĒāĻžā§°ā§āĻĨāĻ•ā§āĻ¯ āĻ•āĻŋāĻŽāĻžāĻ¨ ?) Options / āĻŦāĻŋāĻ•āĻ˛ā§āĻĒāĻ¸āĻŽā§‚āĻš: A. 2  B. 4  C. 8  D. 12


Q4. A bag contains ₹1 and ₹2 coins. The total number of coins is 18 and their total value is ₹28. What is the difference between the number of ₹2 coins and ₹1 coins ? (āĻāĻŸāĻž āĻŦā§‡āĻ—āĻ¤ ₹ā§§ āĻ†ā§°ā§ ₹ā§¨ āĻŸāĻ•āĻžā§° āĻŽā§āĻĻā§ā§°āĻž āĻ†āĻ›ā§‡āĨ¤ āĻŽā§āĻ  āĻŽā§āĻĻā§ā§°āĻž ā§§ā§ŽāĻŸāĻž āĻ†ā§°ā§ āĻŽā§āĻ  āĻŽā§‚āĻ˛ā§āĻ¯ ₹ā§¨ā§ŽāĨ¤ āĻĒāĻžā§°ā§āĻĨāĻ•ā§āĻ¯ āĻ•āĻŋāĻŽāĻžāĻ¨ ?) Options / āĻŦāĻŋāĻ•āĻ˛ā§āĻĒāĻ¸āĻŽā§‚āĻš: A. 2  B. 4  C. 8  D. 10


Q5. A bag contains ₹1 and ₹2 coins. The total number of coins is 25 and their total value is ₹39. What is the difference between the number of ₹2 coins and ₹1 coins ? (āĻāĻŸāĻž āĻŦā§‡āĻ—āĻ¤ ₹ā§§ āĻ†ā§°ā§ ₹ā§¨ āĻŸāĻ•āĻžā§° āĻŽā§āĻĻā§ā§°āĻž āĻ†āĻ›ā§‡āĨ¤ āĻŽā§āĻ  āĻŽā§āĻĻā§ā§°āĻž ā§¨ā§ĢāĻŸāĻž āĻ†ā§°ā§ āĻŽā§āĻ  āĻŽā§‚āĻ˛ā§āĻ¯ ₹ā§Šā§¯āĨ¤ āĻĒāĻžā§°ā§āĻĨāĻ•ā§āĻ¯ āĻ•āĻŋāĻŽāĻžāĻ¨ ?) Options / āĻŦāĻŋāĻ•āĻ˛ā§āĻĒāĻ¸āĻŽā§‚āĻš: A. 3  B. 7  C. 11  D. 14


Ans Key: 1–A 2–B 3–B 4–A 5–A


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Q. A washing machine costs 10% less than a TV. If the washing machine price increases by 65% and the TV price decreases by 34%, then what is the percentage change in the total cost of 5 washing machines and 3 TVs ? (āĻāĻŸāĻž ā§ąāĻžāĻļā§āĻŦāĻŋāĻ‚ āĻŽā§‡āĻšāĻŋāĻ¨ā§° āĻĻāĻžāĻŽ āĻāĻŸāĻž TV-ā§° āĻĻāĻžāĻŽāĻ¤āĻ•ā§ˆ ā§§ā§Ļ% āĻ•āĻŽāĨ¤ āĻ¯āĻĻāĻŋ ā§ąāĻžāĻļā§āĻŦāĻŋāĻ‚ āĻŽā§‡āĻšāĻŋāĻ¨ā§° āĻĻāĻžāĻŽ ā§Ŧā§Ģ% āĻŦā§ƒāĻĻā§āĻ§āĻŋ āĻĒāĻžāĻ¯āĻŧ āĻ†ā§°ā§ TV-ā§° āĻĻāĻžāĻŽ ā§Šā§Ē% āĻšā§ā§°āĻžāĻ¸ āĻĒāĻžāĻ¯āĻŧ, āĻ¤ā§‡āĻ¨ā§āĻ¤ā§‡ ā§ĢāĻŸāĻž ā§ąāĻžāĻļā§āĻŦāĻŋāĻ‚ āĻŽā§‡āĻšāĻŋāĻ¨ āĻ†ā§°ā§ ā§ŠāĻŸāĻž TV-ā§° āĻŽā§āĻ  āĻŽā§‚āĻ˛ā§āĻ¯āĻ¤ āĻ•āĻŋāĻŽāĻžāĻ¨ āĻļāĻ¤āĻžāĻ‚āĻļ āĻĒā§°āĻŋāĻŦā§°ā§āĻ¤āĻ¨ āĻš'āĻŦ ?) Options: A. 25.4% Increase B. 24% Increase C. 18% Decrease D. 19% Decrease


Short Trick


Assume TV = ₹100


Then Washing Machine = ₹90 (10% less)


Original Total







  • 5 WM = 5 × 90 = ₹450

  • 3 TV = 3 × 100 = ₹300


Total = â‚š750


New Prices



  • WM = 90 × 165% = ₹148.5

  • TV = 100 × 66% = ₹66


New Total



  • 5 WM = 5 × 148.5 = ₹742.5

  • 3 TV = 3 × 66 = ₹198


New Total = â‚š940.5


Percentage Change : 940.5 − 750 / 750 × 100 = 190.5 / 750 × 100 = 25.4%


Ans: A. 25.4% Increase (25.4% āĻŦā§ƒāĻĻā§āĻ§āĻŋ / āĻŦā§ƒāĻĻā§āĻ§āĻŋ)


Practice Set – Percentage Change in Prices


Q1. A refrigerator costs 20% less than an air conditioner. If the refrigerator's price increases by 50% and the air conditioner's price decreases by 20%, what is the percentage change in the total cost of 4 refrigerators and 5 air conditioners ? (āĻāĻŸāĻž āĻĢā§ā§°āĻŋāĻœā§° āĻĻāĻžāĻŽ āĻāĻŸāĻž AC-āĻ¤āĻ•ā§ˆ ā§¨ā§Ļ% āĻ•āĻŽāĨ¤ āĻĢā§ā§°āĻŋāĻœā§° āĻĻāĻžāĻŽ ā§Ģā§Ļ% āĻŦā§ƒāĻĻā§āĻ§āĻŋ āĻĒāĻžāĻ¯āĻŧ āĻ†ā§°ā§ AC-ā§° āĻĻāĻžāĻŽ ā§¨ā§Ļ% āĻšā§ā§°āĻžāĻ¸ āĻĒāĻžāĻ¯āĻŧāĨ¤ ā§ĒāĻŸāĻž āĻĢā§ā§°āĻŋāĻœ āĻ†ā§°ā§ ā§ĢāĻŸāĻž AC-ā§° āĻŽā§āĻ  āĻŽā§‚āĻ˛ā§āĻ¯āĻ¤ āĻ•āĻŋāĻŽāĻžāĻ¨ āĻļāĻ¤āĻžāĻ‚āĻļ āĻĒā§°āĻŋāĻŦā§°ā§āĻ¤āĻ¨ āĻš'āĻŦ ?)


A. 8% Increase B. 10% Increase C. 12% Increase D. 15% Increase


Q2. A laptop costs 25% less than a desktop. If the laptop's price increases by 40% and the desktop's price decreases by 10%, what is the percentage change in the total cost of 3 laptops and 2 desktops? (āĻāĻŸāĻž āĻ˛ā§‡āĻĒāĻŸāĻĒā§° āĻĻāĻžāĻŽ āĻāĻŸāĻž āĻĄā§‡āĻ¸ā§āĻ•āĻŸāĻĒāĻ¤āĻ•ā§ˆ ā§¨ā§Ģ% āĻ•āĻŽāĨ¤ āĻ˛ā§‡āĻĒāĻŸāĻĒā§° āĻĻāĻžāĻŽ ā§Ēā§Ļ% āĻŦā§ƒāĻĻā§āĻ§āĻŋ āĻĒāĻžāĻ¯āĻŧ āĻ†ā§°ā§ āĻĄā§‡āĻ¸ā§āĻ•āĻŸāĻĒā§° āĻĻāĻžāĻŽ ā§§ā§Ļ% āĻšā§ā§°āĻžāĻ¸ āĻĒāĻžāĻ¯āĻŧāĨ¤ ā§ŠāĻŸāĻž āĻ˛ā§‡āĻĒāĻŸāĻĒ āĻ†ā§°ā§ ā§¨āĻŸāĻž āĻĄā§‡āĻ¸ā§āĻ•āĻŸāĻĒā§° āĻŽā§āĻ  āĻŽā§‚āĻ˛ā§āĻ¯āĻ¤ āĻ•āĻŋāĻŽāĻžāĻ¨ āĻļāĻ¤āĻžāĻ‚āĻļ āĻĒā§°āĻŋāĻŦā§°ā§āĻ¤āĻ¨ āĻš'āĻŦ ?)


A. 12% Increase B. 15% Increase C. 18% Increase D. 20% Increase


Q3. A chair costs 20% less than a table. If the chair's price increases by 25% and the table's price decreases by 10%, what is the percentage change in the total cost of 5 chairs and 4 tables ? (āĻāĻŸāĻž āĻšāĻ•ā§€ā§° āĻĻāĻžāĻŽ āĻāĻŸāĻž āĻŸā§‡āĻŦā§āĻ˛āĻ¤āĻ•ā§ˆ ā§¨ā§Ļ% āĻ•āĻŽāĨ¤ āĻšāĻ•ā§€ā§° āĻĻāĻžāĻŽ ā§¨ā§Ģ% āĻŦā§ƒāĻĻā§āĻ§āĻŋ āĻĒāĻžāĻ¯āĻŧ āĻ†ā§°ā§ āĻŸā§‡āĻŦā§āĻ˛ā§° āĻĻāĻžāĻŽ ā§§ā§Ļ% āĻšā§ā§°āĻžāĻ¸ āĻĒāĻžāĻ¯āĻŧāĨ¤ ā§ĢāĻŸāĻž āĻšāĻ•ā§€ āĻ†ā§°ā§ ā§ĒāĻŸāĻž āĻŸā§‡āĻŦā§āĻ˛ā§° āĻŽā§āĻ  āĻŽā§‚āĻ˛ā§āĻ¯āĻ¤ āĻ•āĻŋāĻŽāĻžāĻ¨ āĻļāĻ¤āĻžāĻ‚āĻļ āĻĒā§°āĻŋāĻŦā§°ā§āĻ¤āĻ¨ āĻš'āĻŦ ?)


A. 2% Increase B. 4% Increase C. 6% Increase D. 8% Increase


Q4. A mobile phone costs 10% less than a tablet. If the mobile's price increases by 20% and the tablet's price decreases by 10%, what is the percentage change in the total cost of 6 mobiles and 4 tablets ? (āĻāĻŸāĻž āĻŽā§‹āĻŦāĻžāĻ‡āĻ˛ā§° āĻĻāĻžāĻŽ āĻāĻŸāĻž āĻŸā§‡āĻŦāĻ˛ā§‡āĻŸāĻ¤āĻ•ā§ˆ ā§§ā§Ļ% āĻ•āĻŽāĨ¤ āĻŽā§‹āĻŦāĻžāĻ‡āĻ˛ā§° āĻĻāĻžāĻŽ ā§¨ā§Ļ% āĻŦā§ƒāĻĻā§āĻ§āĻŋ āĻĒāĻžāĻ¯āĻŧ āĻ†ā§°ā§ āĻŸā§‡āĻŦāĻ˛ā§‡āĻŸā§° āĻĻāĻžāĻŽ ā§§ā§Ļ% āĻšā§ā§°āĻžāĻ¸ āĻĒāĻžāĻ¯āĻŧāĨ¤ ā§ŦāĻŸāĻž āĻŽā§‹āĻŦāĻžāĻ‡āĻ˛ āĻ†ā§°ā§ ā§ĒāĻŸāĻž āĻŸā§‡āĻŦāĻ˛ā§‡āĻŸā§° āĻŽā§āĻ  āĻŽā§‚āĻ˛ā§āĻ¯āĻ¤ āĻ•āĻŋāĻŽāĻžāĻ¨ āĻļāĻ¤āĻžāĻ‚āĻļ āĻĒā§°āĻŋāĻŦā§°ā§āĻ¤āĻ¨ āĻš'āĻŦ? ) A. 4% Increase B. 5% Increase C. 6% Increase D. 8% Increase


Q5. A bicycle costs 30% less than a scooter. If the bicycle's price increases by 60% and the scooter's price decreases by 20%, what is the percentage change in the total cost of 5 bicycles and 2 scooters ? (āĻāĻŸāĻž āĻšāĻžāĻ‡āĻ•ā§‡āĻ˛ā§° āĻĻāĻžāĻŽ āĻāĻŸāĻž āĻ¸ā§āĻ•ā§āĻŸāĻžā§°āĻ¤āĻ•ā§ˆ ā§Šā§Ļ% āĻ•āĻŽāĨ¤ āĻšāĻžāĻ‡āĻ•ā§‡āĻ˛ā§° āĻĻāĻžāĻŽ ā§Ŧā§Ļ% āĻŦā§ƒāĻĻā§āĻ§āĻŋ āĻĒāĻžāĻ¯āĻŧ āĻ†ā§°ā§ āĻ¸ā§āĻ•ā§āĻŸāĻžā§°ā§° āĻĻāĻžāĻŽ ā§¨ā§Ļ% āĻšā§ā§°āĻžāĻ¸ āĻĒāĻžāĻ¯āĻŧāĨ¤ ā§ĢāĻŸāĻž āĻšāĻžāĻ‡āĻ•ā§‡āĻ˛ āĻ†ā§°ā§ ā§¨āĻŸāĻž āĻ¸ā§āĻ•ā§āĻŸāĻžā§°ā§° āĻŽā§āĻ  āĻŽā§‚āĻ˛ā§āĻ¯āĻ¤ āĻ•āĻŋāĻŽāĻžāĻ¨ āĻļāĻ¤āĻžāĻ‚āĻļ āĻĒā§°āĻŋāĻŦā§°ā§āĻ¤āĻ¨ āĻš'āĻŦ ?)


A. 20% Increase B. 24% Increase C. 28% Increase D. 32% Increase


Ans Key: 1. A (8% Increase),  2. B (15% Increase), 3. B (4% Increase) ,  4. C (6% Increase), 5. C (28% Increase)


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Q. A washing machine costs 10% less than a TV. If the washing machine price increases by 65% and the TV price decreases by 34%, then what is the percentage change in the total cost of 5 washing machines and 3 TVs ? (āĻāĻŸāĻž ā§ąāĻžāĻļā§āĻŦāĻŋāĻ‚ āĻŽā§‡āĻšāĻŋāĻ¨ā§° āĻĻāĻžāĻŽ āĻāĻŸāĻž TV-ā§° āĻĻāĻžāĻŽāĻ¤āĻ•ā§ˆ ā§§ā§Ļ% āĻ•āĻŽāĨ¤ āĻ¯āĻĻāĻŋ ā§ąāĻžāĻļā§āĻŦāĻŋāĻ‚ āĻŽā§‡āĻšāĻŋāĻ¨ā§° āĻĻāĻžāĻŽ ā§Ŧā§Ģ% āĻŦā§ƒāĻĻā§āĻ§āĻŋ āĻĒāĻžāĻ¯āĻŧ āĻ†ā§°ā§ TV-ā§° āĻĻāĻžāĻŽ ā§Šā§Ē% āĻšā§ā§°āĻžāĻ¸ āĻĒāĻžāĻ¯āĻŧ, āĻ¤ā§‡āĻ¨ā§āĻ¤ā§‡ ā§ĢāĻŸāĻž ā§ąāĻžāĻļā§āĻŦāĻŋāĻ‚ āĻŽā§‡āĻšāĻŋāĻ¨ āĻ†ā§°ā§ ā§ŠāĻŸāĻž TV-ā§° āĻŽā§āĻ  āĻŽā§‚āĻ˛ā§āĻ¯āĻ¤ āĻ•āĻŋāĻŽāĻžāĻ¨ āĻļāĻ¤āĻžāĻ‚āĻļ āĻĒā§°āĻŋāĻŦā§°ā§āĻ¤āĻ¨ āĻš'āĻŦ ?)


Options: A. 25.4% Increase B. 24% Increase C. 18% Decrease D. 19% Decrease


Short Trick


Assume TV = ₹100


Then Washing Machine = ₹90 (10% less)


Original Total



  • 5 WM = 5 × 90 = ₹450

  • 3 TV = 3 × 100 = ₹300


Total = ₹750


New Prices



  • WM = 90 × 165% = ₹148.5

  • TV = 100 × 66% = ₹66


New Total



  • 5 WM = 5 × 148.5 = ₹742.5

  • 3 TV = 3 × 66 = ₹198


New Total = ₹940.5


Percentage Change: 940.5 − 750 / 750 × 100 = 190.5 / 750  ×100 = 25.4%


Ans: A. 25.4% Increase (25.4% āĻŦā§ƒāĻĻā§āĻ§āĻŋ / āĻŦā§ƒāĻĻā§āĻ§āĻŋ)


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Practice Set – Percentage Change in Prices


Q1. A refrigerator costs 20% less than an air conditioner. If the refrigerator's price increases by 50% and the air conditioner's price decreases by 20%, what is the percentage change in the total cost of 4 refrigerators and 5 air conditioners ? (āĻāĻŸāĻž āĻĢā§ā§°āĻŋāĻœā§° āĻĻāĻžāĻŽ āĻāĻŸāĻž AC-āĻ¤āĻ•ā§ˆ ā§¨ā§Ļ% āĻ•āĻŽāĨ¤ āĻĢā§ā§°āĻŋāĻœā§° āĻĻāĻžāĻŽ ā§Ģā§Ļ% āĻŦā§ƒāĻĻā§āĻ§āĻŋ āĻĒāĻžāĻ¯āĻŧ āĻ†ā§°ā§ AC-ā§° āĻĻāĻžāĻŽ ā§¨ā§Ļ% āĻšā§ā§°āĻžāĻ¸ āĻĒāĻžāĻ¯āĻŧāĨ¤ ā§ĒāĻŸāĻž āĻĢā§ā§°āĻŋāĻœ āĻ†ā§°ā§ ā§ĢāĻŸāĻž AC-ā§° āĻŽā§āĻ  āĻŽā§‚āĻ˛ā§āĻ¯āĻ¤ āĻ•āĻŋāĻŽāĻžāĻ¨ āĻļāĻ¤āĻžāĻ‚āĻļ āĻĒā§°āĻŋāĻŦā§°ā§āĻ¤āĻ¨ āĻš'āĻŦ ? )


A. 8% Increase B. 10% Increase C. 12% Increase D. 15% Increase


Q2. A laptop costs 25% less than a desktop. If the laptop's price increases by 40% and the desktop's price decreases by 10%, what is the percentage change in the total cost of 3 laptops and 2 desktops ? (āĻāĻŸāĻž āĻ˛ā§‡āĻĒāĻŸāĻĒā§° āĻĻāĻžāĻŽ āĻāĻŸāĻž āĻĄā§‡āĻ¸ā§āĻ•āĻŸāĻĒāĻ¤āĻ•ā§ˆ ā§¨ā§Ģ% āĻ•āĻŽāĨ¤ āĻ˛ā§‡āĻĒāĻŸāĻĒā§° āĻĻāĻžāĻŽ ā§Ēā§Ļ% āĻŦā§ƒāĻĻā§āĻ§āĻŋ āĻĒāĻžāĻ¯āĻŧ āĻ†ā§°ā§ āĻĄā§‡āĻ¸ā§āĻ•āĻŸāĻĒā§° āĻĻāĻžāĻŽ ā§§ā§Ļ% āĻšā§ā§°āĻžāĻ¸ āĻĒāĻžāĻ¯āĻŧāĨ¤ ā§ŠāĻŸāĻž āĻ˛ā§‡āĻĒāĻŸāĻĒ āĻ†ā§°ā§ ā§¨āĻŸāĻž āĻĄā§‡āĻ¸ā§āĻ•āĻŸāĻĒā§° āĻŽā§āĻ  āĻŽā§‚āĻ˛ā§āĻ¯āĻ¤ āĻ•āĻŋāĻŽāĻžāĻ¨ āĻļāĻ¤āĻžāĻ‚āĻļ āĻĒā§°āĻŋāĻŦā§°ā§āĻ¤āĻ¨ āĻš'āĻŦ ?)                        A. 12% Increase B. 15% Increase C. 18% Increase D. 20% Increase


Q3. A chair costs 20% less than a table. If the chair's price increases by 25% and the table's price decreases by 10%, what is the percentage change in the total cost of 5 chairs and 4 tables ? (āĻāĻŸāĻž āĻšāĻ•ā§€ā§° āĻĻāĻžāĻŽ āĻāĻŸāĻž āĻŸā§‡āĻŦā§āĻ˛āĻ¤āĻ•ā§ˆ ā§¨ā§Ļ% āĻ•āĻŽāĨ¤ āĻšāĻ•ā§€ā§° āĻĻāĻžāĻŽ ā§¨ā§Ģ% āĻŦā§ƒāĻĻā§āĻ§āĻŋ āĻĒāĻžāĻ¯āĻŧ āĻ†ā§°ā§ āĻŸā§‡āĻŦā§āĻ˛ā§° āĻĻāĻžāĻŽ ā§§ā§Ļ% āĻšā§ā§°āĻžāĻ¸ āĻĒāĻžāĻ¯āĻŧāĨ¤ ā§ĢāĻŸāĻž āĻšāĻ•ā§€ āĻ†ā§°ā§ ā§ĒāĻŸāĻž āĻŸā§‡āĻŦā§āĻ˛ā§° āĻŽā§āĻ  āĻŽā§‚āĻ˛ā§āĻ¯āĻ¤ āĻ•āĻŋāĻŽāĻžāĻ¨ āĻļāĻ¤āĻžāĻ‚āĻļ āĻĒā§°āĻŋāĻŦā§°ā§āĻ¤āĻ¨ āĻš'āĻŦ ?)


A. 2% Increase B. 4% Increase C. 6% Increase D. 8% Increase


Ans Key : 1. A (8% Increase)  2. B (15% Increase)  3. B (4% Increase)


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Q. Find the Simple Interest (in ₹) on ₹4,000 at 6% per annum from 19 February 2024 to 20 April 2024. (ā§§ā§¯ āĻĢā§‡āĻŦā§ā§°ā§ā§ąāĻžā§°ā§€ ā§¨ā§Ļā§¨ā§Ēā§° āĻĒā§°āĻž ā§¨ā§Ļ āĻāĻĒā§ā§°āĻŋāĻ˛ ā§¨ā§Ļā§¨ā§ĒāĻ˛ā§ˆ ₹ā§Ē,ā§Ļā§Ļā§Ļ āĻŸāĻ•āĻžā§° āĻ“āĻĒā§°āĻ¤ āĻŦāĻžā§°ā§āĻˇāĻŋāĻ• ā§Ŧ% āĻ¸ā§°āĻ˛ āĻ¸ā§āĻ¤āĻ¤ āĻ¸ā§°āĻ˛ āĻ¸ā§āĻ¤ (₹āĻ¤) āĻ¨āĻŋā§°ā§āĻŖāĻ¯āĻŧ āĻ•ā§°āĻ•āĨ¤)


Options: A. ₹39  B. ₹41  C. ₹38  D. ₹40


Short Trick


1st: Find the number of days (āĻĻāĻŋāĻ¨ āĻ—āĻŖāĻ¨āĻž)



  • February: 19 to 29 = 10 days

  • March: 31 days

  • April: 1 to 20 = 20 days


Total = 10 + 31 + 20 = 61 days


2nd: Simple Interest Formula : SI = P × R × T / 100




Simple Interest = ₹40


Ans: D. ₹40


Note: Use 366 days for a leap year (e.g., 2024) and 365 days for a non-leap year.


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Practice Set – Simple Interest (Days Based)


Q1. Find the Simple Interest on ₹6,000 at 5% per annum from 1 January 2024 to 1 March 2024. (ā§§ āĻœāĻžāĻ¨ā§ā§ąāĻžā§°ā§€ ā§¨ā§Ļā§¨ā§Ēā§° āĻĒā§°āĻž ā§§ āĻŽāĻžā§°ā§āĻš ā§¨ā§Ļā§¨ā§ĒāĻ˛ā§ˆ ₹ā§Ŧ,ā§Ļā§Ļā§Ļ āĻŸāĻ•āĻžā§° āĻ“āĻĒā§°āĻ¤ āĻŦāĻžā§°ā§āĻˇāĻŋāĻ• ā§Ģ% āĻ¸ā§°āĻ˛ āĻ¸ā§āĻ¤āĻ¤ āĻ¸ā§°āĻ˛ āĻ¸ā§āĻ¤ āĻ¨āĻŋā§°ā§āĻŖāĻ¯āĻŧ āĻ•ā§°āĻ•āĨ¤) Option: A. ₹48  B. ₹49  C. ₹50  D. ₹51


Q2. Find the Simple Interest on ₹3,000 at 8% per annum from 15 March 2024 to 14 May 2024. (ā§§ā§Ģ āĻŽāĻžā§°ā§āĻš ā§¨ā§Ļā§¨ā§Ēā§° āĻĒā§°āĻž ā§§ā§Ē āĻŽā§‡' ā§¨ā§Ļā§¨ā§ĒāĻ˛ā§ˆ ₹ā§Š,ā§Ļā§Ļā§Ļ āĻŸāĻ•āĻžā§° āĻ“āĻĒā§°āĻ¤ āĻŦāĻžā§°ā§āĻˇāĻŋāĻ• ā§Ž% āĻ¸ā§°āĻ˛ āĻ¸ā§āĻ¤āĻ¤ āĻ¸ā§°āĻ˛ āĻ¸ā§āĻ¤ āĻ¨āĻŋā§°ā§āĻŖāĻ¯āĻŧ āĻ•ā§°āĻ•āĨ¤) Option: A. ₹39  B. ₹40  C. ₹41  D. ₹42

 

Q3. Find the Simple Interest on ₹5,000 at 9% per annum from 10 June 2024 to 9 August 2024. (ā§§ā§Ļ āĻœā§āĻ¨ ā§¨ā§Ļā§¨ā§Ēā§° āĻĒā§°āĻž ā§¯ āĻ†āĻ—āĻˇā§āĻŸ ā§¨ā§Ļā§¨ā§ĒāĻ˛ā§ˆ ₹ā§Ģ,ā§Ļā§Ļā§Ļ āĻŸāĻ•āĻžā§° āĻ“āĻĒā§°āĻ¤ āĻŦāĻžā§°ā§āĻˇāĻŋāĻ• ā§¯% āĻ¸ā§°āĻ˛ āĻ¸ā§āĻ¤āĻ¤ āĻ¸ā§°āĻ˛ āĻ¸ā§āĻ¤ āĻ¨āĻŋā§°ā§āĻŖāĻ¯āĻŧ āĻ•ā§°āĻ•āĨ¤) Option: A. ₹74  B. ₹75  C. ₹76  D. ₹77