Question

A tank of diesel fuel contains 210 gallons. Every week, 5 gallons is used. A tank of gasoline contains 430 gallons. Every week, 16 gallons is used. After how many weeks will they have the same amount of fuel? How much fuel will each tank hold on that day?

Answer 1

After 20 weeks both tanks have the same amount of fuel.

Diesel tank= 110 gallons

Gasoline tank= 110 gallons

Explanation:

Giving the following information:

Diesel tank:

Total capacity= 210 gallons

Unitary daily use= 5 gallons

Gasoline tank:

Total capacity= 430 gallons

Unitary daily use= 16 gallons

First, we structure the total fuel loss formula for each tank:

Diesel tank= 210 - 5*x

Gasoline tank= 430 - 16*x

x= number of weeks

Now, we equal both formulas and isolate x:

210 - 5x = 430 - 16x

11x = 220

x= 20

After 20 weeks both tanks have the same amount of fuel.

Prove:

Diesel tank= 210 - 5*20= 110 gallons

Gasoline tank= 430 - 16*20= 110 gallons