Question

There are white, green and blue beads

in a bag.
The ratio of white beads to green beads
is 2:5
The ratio of green beads to blue beads
is 1:3
Work out the ratio of white beads to blue
beads

Answer 1

Answer is 2:15

Reason:

The ratio of white to green is 2:5.

The ratio of green to blue is 1:3, which can be scaled up to 5:15 after multiplying both parts by 5.

Write out the ratios 2:5 and 5:15 to notice that we have the inner '5's match up. This gives a triple ratio of 2:5:15 which is the ratio of white to green to blue in that exact order.

Ignoring the middle value gives the ratio of white to blue being 2:15

For every 2 white beads, there are 15 blue beads.