If the ratio of the purple flowers to black flowers is 4 to 8 and there are a total of 108 flowers, how many of the flowers are purple

36 flowers would be purple. Here's why:

The ratio 4:8 is the same as 1:2. This means that of every three flows, 1 is purple and 2 are black.

Since 1/3 of the flowers are purple, you'd take 108 x (1/3), or simply divide by 3. Your answer would be 36, and that's how many flowers are purple.