The three-digit number "ab5" is divisible by 3. How many different three-digit numbers can "ab5" represent?
The smallest 3-digit number divisible by 3 and ending in 5 is 105. The largest 3-digit number divisible by 3 and ending in 5 is 975. Each number after 105 must increase by increments of 30 in order to be divisible by 3 and ending in 5.
Therefore: 975 -105 = 870 / 30 + 1 = 30 numbers that are divisible by 3 and end in 5.
