In my fish tank, the ratio of red fish to blue fish is 1: 5. there are 15 blue fish. how many red fish are there?

The ratio of red fish to blue fish is 1:5

That means that for every one red fish you have, there are 5 blue fish. In this scenario, there are 15 blue fish.

What can you multiply 5 by to equal 15?
The answer is 3. Multiply each side of the ratio by 3

1x3=3 and 5x3=15

The new ratio is 3:15, meaning if there are 15 blue fish, there are 3 red ones

I hope that makes sense!