Question

The ratio between the speeds of two trains is 7 is 28 if the second train is runs 400 km is 4 hours then the speed of the first train is

Answer 1

Speed = Distance/ Time

2nd train:— speed = 400/5

= 80 km/hr

1st train speed = (80/8)*7 km/hr

= 70 km/hr

Answer 2

Let, the speed of first train is 7x. And

the speed of second train is 28x.

According to the question.

Since, the speed of second train is 400km in 4 hour.

we know that,

: Distance=speed×time

Here, the speed of second train is 28x. and

Distance=400km

time =4 hour

now,

400 = (28x ) ×( 4)

x = 400/28×4

x =25/7

Hence,

the speed of first train= 7x

=7×25/7

= 25km/ the speed of second train is=28x

=28×25/7

=100km/h. Ans