how many integers from 22 to 160 , inclusive , are divisible by 3 but not divisible by 7 ?
"we should find # of integers divisible by 3 but not by 3 * 7 = 21 . # of multiples of 21 in the range from 22 to 160 , inclusive is ( 147 - 42 ) / 21 + 1 = 6 ; 46 - 6 = 40 . answer : c ."
divide(160, const_10)