Question

How many integers between 10 and 40, inclusive, can be divided by 3 with a remainder of 0?

Answer 1

Answer: 10

Explanation:

First, we want to find the lowest multiple of 3 above 10. (A remainder of 0 means it's perfectly divisible by 3.) The lowest multiple of 3 above 10 is 12. And so we just count by 3s until we pass 40.

12, 15, 18, 21, 24, 27, 30, 33, 36, 39.

That's 10 numbers. If you keep going past that, you get 42, which is greater than 40, so it does not count.