Question

{0, 1, 2, 3, 4, . . . , 148, 149, 150} How many members of the above set are multiples of 3 but not multiples of 5? *

Answer 1

Answer:

The answer is 40.  

Step-by-step explanation:

First you can simply just list the multiples of 3 from 1-150, then cancel out all the multiples of 5 so,

3, 6, 9, 12, 18, 21, 24, 27, 33, 36, 39, 42, 48, 51, 54, 57, 63, 66, 69, 72, 78, 81, 84, 87, 93, 96, 99, 102, 108, 111, 114, 117, 123, 126, 129, 132, 138, 141, 144, 147.

15,30,45, 60,75,90, 105, 120,135 and 150 are multiples of 5 and so they are not included.