To make fruit punch marcus mixes orange juice and pineapple juice in the ratio 5 to 2 if he uses 2.5 gallons of pineapple juice how many gallons of orange juice will he use? number 7

The ratio in here is orange juice to pineapple juice (specifically 5 gallons of orange juice to 2 gallons of pineapple juice). We need to figure out how many gallons of orange juice needs to be used if Marcus has 2.5 gallons of pineapple juice. 



If you solve this proportion you should get: 
5(2.5) = 2x 
12.5 = 2x 
12. 5 / 2 = 2x / 2
6.25 = x

Marcus needs 6.25 gallons of orange juice.