SOLUTION: How many integers between 1 and 200 are multiples of both 3 and 5 but not of either 4 or 7?

Algebra ->  Divisibility and Prime Numbers -> SOLUTION: How many integers between 1 and 200 are multiples of both 3 and 5 but not of either 4 or 7?      Log On


   

Question 539852: How many integers between 1 and 200 are multiples of both 3 and 5 but not of either 4 or 7?
Answer by JBarnum(2146) About Me  (Show Source):
You can put this solution on YOUR website!
use the 3 trick when counting with 5s starting at 15 1+5=6 so its divisible by 3
15,30,45,60,75,90,105,120,135,150,165,180,195
above are the possibilities for 3 n 5 but some are divisible by 4 and 7 so go through and knock those out
15,30,45,cross%2860%29,75,90,cross%28105%29,cross%28120%29,135,150,165,cross%28180%29,195