Question

Q. The ratio between the speeds of two trains is 7: 8. If the second train runs 400 Kms. In 5
hours, the speed of the first train is:

(a) 10Km/hr
(b) 50 Km/hr
(c) 70 Km/hr
(d) none of these ​

Answer 1

$\huge \bold \red{answer : }$

c) 70 km/hr

◦•●◉✿explain:✿◉●•◦

Speed = Distance/ Time 2nd train:— speed = 400/5 = 80 km/hr 1st train speed = (80/8)*7 km/hr = 70 km/ hr.

Answer 2

Answer :–

• The correct one is option (c) 70km/hr.

Given :–

• Speed of two trains is 7:8
• Second train runs 400kms in 5 hrs.

To Find :–

• Speed of first train.

Solution :–

Let,

The speed of two trains be 7x and 8x.

First, we need to find the value of x.

Given that,

Second train runs 400kms in 5hrs.

• Second train = 8x

⟹ 8x = $\dfrac{\cancel{400}}{\cancel{5}}$

⟹ 8x = 80

⟹ x = $\dfrac{\cancel{80}}{\cancel{8}}$

⟹ x = 10

Now, we have to find the speed of first train.

So,

• First train = 7x

• Value of x = 10

So,

⟹ 7 × 10

⟹ 70km/hr

Hence,

The speed of the first train is 70km/hr.

So, the correct option is (c) 70km/hr.