A gasoline tank on a certain tractor holds 16 gallons of gasoline. If the tractor requires 7 gallons to plow 3 acres, how many acres can the tractor plow with a tankful of gasoline?
A. 6
B. 7
C. 7
D. 10
E. 37
Hint : Think of setting up this problem as a ratio of the form “a is to b as c is to d,” which is mathematically equivalent to = . If 7 gallons of gasoline can plow 3 acres, then is . Knowing that it represents the same proportion, what is ? Since there will only be one unknown variable, that variable can be solved for directly to find the answer.
Here's Why: In the question, you are told that 7 gallons of gasoline can plow 3 acres and you are asked to find how many acres, call it x, can be plowed by 16 gallons. You can set up a ratio of the number of gallons of gasoline used to the number of acres plowed. Therefore, you have = . Cross-multiplying and solving for x gives you the answer of x = acres, or 6 acres.
Difficulty: Easy
Question Type: Standard Multiple Choice
(Mathematics)
= 
. If 7 gallons of gasoline can plow 3 acres, then 
. Knowing that it represents the same proportion, what is 
. Cross-multiplying and solving for x gives you the answer of x = 
acres, or 6
