The speed of two trains are in the ratio 6 : 7. If the second train runs 364 km in 4 hours, then the speed of first train is :

Answer: Option C

Given, Ratio of speed of trains = 6 : 7
Second train covers 364 kms in 4 hours
Then, its speed = $$\frac{364}{4}$$ = 91 km/hr
In the question it is given that speed of the second train = 7 units
But actual speed = 91 km/hr
i.e., 7 units → 91 km
1 unit → 13 km
Therefore,
Speed of the first train is :
= 6R
= 6 × 13
= 78 km/hr