The speed(S) of a car varies partly directly as its mass(M) and partly directly as the quantity (Q) of fuel in it. When the spee
d is 80km/hr, the mass is 220kg and the quantity of fuel is 30litres, when the speed is 60km/hr, the mass is 300kg and the quantity of fuel is 40 litres. Find the volume of fuel if the speed is 100km/hr and the mass 250kg
4/5 was left after the first, which can also be written as 16/20. 16/20 - 1/4 (also written as 5/20), which leaves 11/20 which can also be written as 33/60. 33/60 - 1/3 (also written as 20/60) which leaves 13/60 left.