Question

Find the number of numbers from 1 to 1000 which are neither divisible by 2 nor by 3 nor by 5.

Answer 1

@Zarkon

Answer 2

@experimentX

Answer 3

A = find the number of digits what is divisible by 2
B = find the number of digits what is divisible by 3
C = find the number of digits what is divisible by 5

\( A \cap B \) = number of digits divisible by 2 and 3
\( C \cap B \) = number of digits divisible by 3 and 5
\( C \cap A \) = number of digits divisible by 2 and 5

\( C \cap A \cap B \) = number of digits divisible by 2 and 5 and 3

Answer 4

http://en.wikipedia.org/wiki/Inclusion%E2%80%93exclusion_principle

Answer 5

Thank you sir