Can someone help me out? In 2 weeks, a family drinks 3 gallons of milk. How many gallons will this family drink in 9 weeks?

Answer 1

I think the best way to answer this is to set up what you're trying to find out and what you already know and break the problem down into easier components. Since you know that a family drinks 3 gallons of milk in 2 weeks, how many do they drink in 1? Well, that seems a little simpler than going straight to the question of 9. 1 week is 1/2 of 2 weeks, and 1.5 is 1/2 of 3. So on average, this family drinks 1.5 gallons of milk a week. And if our final question is how much milk is drunk in 9 weeks and we know how much is drunk in 1, then all we need to do is multiply it by 9. So 9 x 1.5 = 13.5. The family drinks 13.5 gallons of milk in 9 weeks.

Answer 2

Assuming that they continue to drink milk at the same rate, setting up a proportion is a good way to solve the question. Make sure that your setup is consistent and check your answer. It should make sense. If not, re-think your setup.

One way would be: 2wks/3 gals = 9 wks/x gals

Cross-multiply: 2x = 27 → x = 13.5 gals.