Question

A freight train takes 16 hours to travel the same distance that an express train travels in 12 hours.If the express train travels 15 km/h faster than the freight train, find the rate of each train

Answer 1

let distance be dkm,

freight train speed be s1km/h and express train speed,s2=(15+s1)km/h

freight train ,d=16s1

express train, d/12=15+s1

16s1=12(15+s1)

s1=45km/h.

so, s2=15+s1

60km/h

Answer 2

Let the speed of freight train be x km/hr
Then, speed of express train is x+15

Since they travel same distance,
$x \times 16 = (x + 15) \times 12 \\ 16x - 12x = 180 \\ x = \frac{180}{4} = 45$
Therefore, speed of freight train is 45 km/hr
speed of express train is 45+15 = 60 km/hr