Problema Solution
a train travels 110 km in the same time that a plane covers 385 km. if the speed of the plane is 20 km per hour less than 4 times the speed of the train, find both speeds
Answer provided by our tutors
Let
x = the speed of the train
y = the speed of the plane
the time that the train travels 110 km = the time that plane travels 385 km
since the formula for the speed is v = s/t where v d = distance, t = time
then for the time we can write t = s/v thus
110 / x = 385 / y
the speed of the plane is 20 km per hour less than 4 times the speed of the train
y = 4*x - 20
By solving the system of equations
110 / x = 385 / y
y = 4*x - 20
we find
x = 40 km/hour
y = 140 km/hour
The speed of the train is 40 km/hour and the speed of the plane is 140 km/hour.