Question

The ratio between the speeds of two trains is 7 : 8. if the second train runs 400 km in 4hours, then the speed of the first train is:

Answer 1

Hey there !

Solution:

Let the speed of two trains be x : y

=> x : y = 7 : 8

Now the Second train covers 400 km in 4 hours

=> Speed of Second Train ( y ) = 400 / 4 = 100 km/hr.

So we get,

=> x : 100 = 7 : 8

Product of means = Product of extremes

=> x * 8 = 100 * 7

=> 8 x = 700

=> x = 700 / 8

=> x = 87.5 km/hr.

Hence the speed of 1st train is 87.5 km/hr.

Hope my answer helped !

Answer 2

Hello dear your answer


Let the speed of the train be x which is 7x and 8X

The second train covered 400km in 4 hours

Speed of the train (y) = 400/4( cancel it we get 100)

100km/hr

So we get
X= 100=7:8

Product of means= Product of extreme
X*8=100*7
8X=700
X= 700/8( by cancelling we get 87.5)
X=87.5km/HR





Their fore the speed of the first train is 87.5km/HR...



Thanks!!!