Question
Question: All possible two factors products are formed from the numbers 1, 2, 3, 4, ….. , 200. The number of f...
All possible two factors products are formed from the numbers 1, 2, 3, 4, ….. , 200. The number of factors out of the total obtained which are multiples of 5 is –
A
5040
B
7180
C
8150
D
None of these
Answer
7180
Explanation
Solution
The total number of two factor products = 200C2. The number of numbers from 1 to 200 which are not multiples of 5 is 160. Therefore the total number of two factor products which are not multiple of 5 is 160C2. Hence, the required number of factors = 200C2 – 100C2 = 7180.