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

Purple flowers: black flowers = 4:8 = 108

4 + 8 = 12

108 / 12 = 9. 

9 x 4 = 36. 

36 of the flowers are purple. 

Ok let's see.

The way to tackle this, is to first add up the ratio's.

So 4+8 = 12. Now this 12 is important as this is total number of shares (bunches) we need to allocate to 2 different flower colours.

Before we can know how much flowers = 4 and 8 bunches. We first need to work out how many flowers = 1 bunch.

It's simple.

108 (total number of flowers) ÷ 12 (bunches of flowers) = 9 flowers per bunch.

So if 1 bunch = 9 flowers.

4 : 8

= (4 bunches x 9 flowers) : (8 bunches x 9 flowers)

Which leads to...

36 purple : 72 black