A painter mixes 2 1/2 pints (2.5 pints) of yellow paint with 4 pints of red paint to make a certain shade of orange paint. The ratio of yellow paint to red paint is 2.5:4. In order to find the pints of yellow paint needed to be mixed with 10 pints of red paint, we will use conversion fractions.
10 red pints × (2.5 yellow pints/ 4 red pints) ≈ 6 pints (we round off to 1 significant figure)
For every 4 pints of red, there are 2 1/12 pints of yellow. 8 of those red pints would make 5 yellow pints. Adding 2 more pints of red to get to the 10 would mean you have to half the 2 1/2, which would be 1 1/2. So, you would need 6 1/2 pints of yellow mixed with the 10 red pints to make the shade of orange. :)
