Show your work please and thank you!

1.5 cleaner / 12 cups of water
or
1.5 cleaner : 12 cups of water
to reduce this ratio of 1.5:12, we need to divide both by the same number

1.5 divided by 1.5 is 1
12 divided by 1.5 is 8

So the ratio of cleaner to water is 1:8 in its simplest form or 1 part cleaner to 8 parts water.

Hope this helps!!  :)