Nate is helping to redesign his basement. He is in charge of choosing and buying the paint. He wants a specific shade of green, so he is going to combine blue and yellow paint in the ratio of 1:3 . If he needs 8 gallons of paint, how much yellow paint does he need to buy?

Answer 1

The total ratio of blue to yellow paint is 1 + 3 = <<1+3=4>>4
The proportion of yellow paint needed is 3/4 = <<3/4=0.75>>0.75
He needs to buy 8 * 0.75 = <<8*0.75=6>>6 gallons of yellow paint. Answer: \boxed{6}.