Question

How many 3 digit numbers are divisible by both 3 and 5 but not by 7?

Answer 1

if you know set theory and probablity,
no of digit divisible by 3 and 5 but not 7 = no of digits divisible by 3+
no of digits divisible by 5 -
no of digits divisible by both 3 and 5+
no. of digits divisible by 105 (i got this as the lcm of 3,5 n 7)

hope this helps. dont forget to mark this as the best response (y)

Answer 2

no of digit divisible by 3 and 5 but not 7 = no of digits divisible by 3+
no of digits divisible by 5 -
no of digits divisible by both 3 and 5 \(\color{red}{-}\)
no. of digits divisible by 105

Answer 3

333+199-66-95=371