Question

A new train goes 20% further in 20% less time than an old train. By what % is the average speed of the new train GREATER THAN that of the old train?

Answer 1

Let Do = 1 mi = Distance of old train.
Dn = 1.2*Do = 1.2 * 1 = 1.2 mi = Dist.
of new train.

Let To = 1min = Time of old train.
Tn = 0.8*To = 0.8 * 1 = 0.8 min. = Time
of new train

Vo=Do/To = 1mi/1min=1mi/min Velocity of old train.
Vn = Dn/Tn = 1.2mi/0.8min = 1.5 mi/min = Velocity of new train.

Vn/Vo = 1.5/1 = 1.5 = 150%,
% Greater = 150% - 100% = 50%.

Answer 2

the answer before mine is wrong becaude it is actually 65%

Answer 3

It's 50%.