An airplane begins a flight with a total of 111 litres of fu

An airplane begins a flight with a total of 111 litres of fuel stored in two separate wing tanks. During the flight 33.3% of the fuel in one tank is used. In the other tank, 50.8% of the fuel is used. If 46 litres of fuel is used in total, find the amount of fuel (in litres) used in each tank during the trip.

Solution

in first tank fuel = x litre

in second tank fuel = y litre

x + y = 111 litre

x*33.3/100 + y*50.8/100 = 46

then solving these equations:

33.3x + 33.3y = 111*33.3

33.3x + 50.8y = 4600

subtracting both equations:

-17.5*y = (111*33.3 - 4600)

y = -(111*33.3 - 4600)/17.5 = 51.64 litre

x = 111 - 51.64 = 59.36 litre