Answer:
3
Explanation:
The problem is first to find the Least Common Multiple (LCM) for the numbers 4, 6 and 8 together.
To find the LCM, we have to break down every number into it's prime factors:
4: 2 x 2 = 2²
6: 2 x 3 = 2 x 3
8: 2 x 2 x 2 = 2³
Then for each prime number listed we pick the highest exponent and we multiply them. For 2, the highest comes from 8 (2³), while for 3 there's only one occurrence... so the choice is easy:
LCM (4,6,8) = 2³ * 3 = 8 * 3 = 24
So, every 24 houses, we'll find all three trolls colors.
How many times will that happen within a group of 75 houses?
3 times of course, at houses #24, #48 and #72.
