How many numbers between 1 and 100 (inclusive) are divisible by 7 or 10?
100/7 = 14 .28 ~ 14 numbers
100/10 =10 numbers
24 numbers total are divisible by 10 or 7
One number ( 70 ) is divisible by 10 AND 7
N (divisible by 7 or 10) = N(divisible by 7) + N (divisible by 10) - N (divisible by 7 and 10) =
(14) + (10) - 1 =
23
Ack ! TRUE ! I counted 70 twice...bummer !