Solve.
-The amount of gas that a helicopter uses varies directly as the number of hours spent flying. The helicopter flies for 2 hours and uses 10 gallons of fuel. Find the number of gallons of fuel that the helicopter uses to fly for 6
Hours.
A)35 gallons
B)36 gallons
C)30 gallons
D)12 gallons

Question

Quizplus · Accepted Answer

If the amount of gas used varies directly with the number of hours spent flying, we can set up a proportion. Let x be the number of gallons of fuel used for 6 hours of flying. 
10/2 = x/6 
Cross-multiplying gives: 
2x = 60 
x = 30 
Therefore, the helicopter uses 30 gallons of fuel to fly for 6 hours. The best choice is C. We can use the direct variation formula:

amount of gas used = k * number of hours

where k is the constant of variation.

To find k, we can use the given information that the helicopter uses 10 gallons for 2 hours:

10 = k * 2

k = 5

Now we can use this value of k to find the amount of gas used for 6 hours:

amount of gas used = 5 * 6 = 30 gallons

Therefore, the answer is choice C.

Solve. -The Amount of Gas That a Helicopter Uses Varies Directly