Factorial : Examples 1

Q. How many 4's are there in 80! ? (প্ৰশ্ন: 80!-ত মুঠ কিমানটা 4 আছে ?)


Soln:


Divide repeatedly by 4: 80 ÷ 4 = 20 , 20 ÷ 4 = 5 , 5 ÷ 4 = 1


Now add: 20 + 5 + 1 = 26


Ans: C. 26


Note: Divide by 4 until the quotient becomes less than 4


Practice Questions



  1. How many 4's are there in 60! ?

  2. How many 4's are there in 120! ?

  3. How many 4's are there in 150! ?

  4. How many 4's are there in 75! ?

  5. How many 4's are there in 90! ?