gallons of fuel math problem

Question

A generator contains 60 gallons of fuel and uses 2.5 gallons per hour. A more efficient power generator contains 40 gallons of fuel and uses 1.5 gallons per hour. After how many hours do the generators have the same amount of fuel?

Answer 1

60 gal - (h hours x 2.5 gal/1 hr) = 40 gal - (h hours x 1.5 gal/1 hr)

60 - h(2.5) = 40 - h(1.5)

20 = h(1)

After 20 hours, the 60 gal tank will have 10 gal left

After 20 hours, the 40 gal tank will have 10 gal lft