Answer: 25 cartons
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Explanation:
1 liter = 1000 mL
Note how 1000/200 = 5, which means that if one carton is 200 mL, then five cartons gets us 5*200 = 1000 mL = 1 liter. If it takes five cartons to get 1 liter, then we'll need five times as many cartons to get to 5 liters. So 5*5 = 25 cartons is our goal.
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We could also solve like this
(1 carton)/(200 mL) = (x cartons)/(5000 mL)
1/200 = x/5000
1*5000 = 200x .... cross multiply
5000 = 200x
200x = 5000
x = 5000/200 ..... divide both sides by 200
x = 25
