These questions were written based on the data in:

*Chapagain A, Hoekstra A (2004)*Water Footprints of Nations Volume One: Main Report.*Value of Water Research Report Series No.16. Delft (The Netherlands): UNESCO - IHE Institute for Water Education.**Aldaya M, Hoekstra A. (2009)*The Water Needed to Have Italians Eat Pasta and Pizza.*Value of Water Research Report Series No.36. Delft (The Netherlands): UNESCO - IHE Institute for Water Education.*

Answers to the questions below are at the bottom of the page.

1) How many liters of water are needed to produce each of the following?

a) A pot of coffee that contains 6 cups?

b) A sandwich consisting of 2 slices of bread with cheese?

c) An omelet made with 2 eggs and 1 tomato?

d) A 50 g serving of potato chips?

2) The number of liters of water needed to produce a glass of milk is how much more than the number of liters needed to produce a cup of coffee?

3) To the nearest tenth, the number of liters of water needed to produce a glass of apple juice is how many times the number of liters needed to produce an apple?

4) The number of liters of water needed to produce a cheese pizza is how many times the number of liters needed to produce a tomato pizza?

5) The number of liters of water needed to produce a slice of bread is what fraction of the number of liters needed to produce a slice of bread with cheese?

6) To the nearest tenth of a percent, the number of liters of water needed to produce a potato is what percent of the number of liters needed to produce a bag of potato chips?

7) The number of liters of water needed to produce a slice of bread is what percent greater than the number of liters needed to produce a potato?

8) The number of liters of water needed to produce a 3 egg omelet is how much greater than the number of liters needed to produce 2 slices of bread?

9) The number of liters of water needed to produce a cheese pizza with 300 g of hamburger meat on it is how many times the number of liters needed to produce a tomato pizza?

10) The number of liters of water needed to produce a tomato pizza is what fraction of the number of liters needed to produce a hamburger?

11) To the nearest whole percent, the number of liters of water needed to produce a sandwich with two slices of bread with 20 g of cheese is what percent of the number of liters needed to produce a hamburger with 20 g of cheese?

12) The number of liters of water needed to produce a hamburger is what percent greater than the number of liters needed to produce a cheese pizza?

1a. Answer: 6 x 140 = 840

2b. Answer: 40 + 90 = 130

3c. Answer 2 x 135 + 13 = 283

4d. Answer: (50/200) x 185 = 46.25

2. Answer: 200 - 140 = 60

3. Answer: 190/70 = 2.7 to the nearest tenth

4. Answer: 1200/300 = 4

5. (Answer 40/90 = 4/9

6. Answer: 25/185 = 13.5%, to the nearest tenth of a percent

7. Answer: (40 - 25) /25= 60%

8. Answer: (3 x 135) - (2 x 40) = 325

9. Answer: (1200 + (2 x 2400))/300 = 20

10. Answer: 300/2400 = 1/8

11. Answer: (2 x 90)/(2400 + (2 x (90-40)) = 7% to the nearest whole percent

12. Answer: (2400 - 1200)/1200 = 100%

*Thanks to Ellen Tattenbaum for writing these questions!*