All possible two factors products are formed from the numbers 1, 2, 3, 4, ....., 200. The number of factors out of total obtained which are multiples of 5 is Choose the correct option:
A) 5040  B) 7180  C) 8150  D) 7280  E) None of these
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 which are multiples of 5 = 200C2 – 160C2 = 7180.   Answer 7180
<result>B</result>
All possible two factors products are formed from the numbers 1, 2, 3, 4, ....., 200. The number of factors out of total obtained which are multiples of 5 is