Question
Quantitative Aptitude Question on Number Systems
Find the minimum numbers starting from 74 that are multiplied to get 50 zeros at the end ?
A
150
B
160
C
180
D
200
Answer
200
Explanation
Solution
To get fifty zeros at the end, there must be fifty 5’s in the multiplication.
The numbers which contribute 5’s are 75, 80, 85……..
Thus, the number of 5’s in each of them = 2 + 1 + 1 + 1 + 1 + 2 + 1 + 1 +………
In the 5 such numbers, six 5s are obtained. To get fifty 5s, 8 such groups are needed. Also note that 125 and 250 will have three 5s.
So, a total of 5 × 8 × 5 = 200 numbers must be multiplied.
So, the correct option is (D) : 200.