Question

two trains have respective speed...​

Answer 1

1st Train Speed=45 km/h

2nd Train Speed=10 m/s

Changing 10 m/s into km/h

Use Formula

$10 \times \frac{18}{5} \\ = 36$

2nd Train Speed=36 km/h

As we know

a:b=a/b

So We can write speed

$\frac{45}{36} \\ \\ \frac{5}{4}$

Ratio=5:4

Hence (a) is Right option

Answer 2

answer is a.

hope it helps....