Math Test 1
The remainder when −46 is divided by 3 is :
Explanation: Find a number that multiplies with 3 close to – 46
• 3 × (–16) = –48
Now: – 46 – (– 48) = –46 + 48 = 2
Ans: The remainder is 2
If Pn represents the product of the natural numbers from 1 to n, then P1+P2+P3+P4 is :
Explanation:
To find P1+P2+P3+P4, we first need to calculate the factorials for each value of nn:
- P1=1!
- P2=2!=2×1=2
- P3=3!=3×2×1=6
- P4=4!=4×3×2×1=24
Now, we sum them up:
P1+P2+P3+P4=1+2+6+24
Calculating the sum:
1+2=3
3+6=9
9+24=33
Thus, the value of P1+P2+P3+P4 is: (B) 33.
A cone has a base radius of 4 cm and height of 9 cm. The volume of the cone is :
Explanation: Volume of a Cone Formula: V=1/3πr2h
Given:
• Radius (r) = 4 cm
• Height (h) = 9 cm
Step-by-step:
• Square the radius: r2=42=16
• Multiply: 16×9=144
• Multiply by 1/3 : 1/3×144=48
Add π: V=48π cm3
Ans: Volume = 48π cm³
If sinθ=cosθ then the value of 1+tanθ is :
Explanation: Given:
Sinθ = Cosθ
Divide both sides by Cosθ
Sinθ / Cosθ = Cosθ/cosθ
tanθ=1
Add 1 to tanθ
1+tanθ = 1+1 = 2
Ans: 2
The least natural number which when divided by 2 gives remainder 1, when divided by 3 gives remainder 2 and when divided by 4 gives remainder 3, is :
Explanation: We are given:
• N = 1(mod 2)
• N = 2(mod 3)
• N = 3(mod 4)
Notice a pattern
We can rewrite each condition like this:
• N+1 is divisible by 2
• N+1 is divisible by 3
• N+1 is divisible by 4
So: N+1 is a common multiple of 2,3,4
Find the least common multiple (LCM)
LCM(2,3,4)=12
So:
N+1=12 ⇒ N=11
But 11 doesn't work for all conditions. Try:
N+1=24 ⇒ N=23
Check N=23
• 23mod 2=1
• 23mod 3=2
• 23mod 4=3
Ans: 23 is the smallest natural number that satisfies all 3 conditions.
72 toffees were distributed to some boys in a group. Each boy in the group got twice as many of the toffees as the number of boys. The number of boys in the group is :
Explanation: Given:
• Each boy gets 2×(number of boys) toffees.
• Total toffees = 72
Let number of boys = x
• Each boy gets 2x toffees
• Total toffees = x × 2x = 2x²
So: 2x²=72
Solve:
x² = 36 (Divide both sides by 2)
x = 6 (Take square root)
Ans: Number of boys = 6
The product of the roots of the quadratic equation 2x2−5x+6=0 is :