A man travels 430 kilometres in, partly by rail and partly by steamer. He spends 10 hours more time on steamer. If the velocity of the steamer is 25 km/hr and the velocity of rail is 65 km/hr, how much distance does he cover by steamer?

Let distance covered by steamer = $$d$$ km

=> Distance covered by rail = $$(430 - d)$$ km

Let time taken on rail = $$t$$ hours and time taken on steamer = $$(t + 10)$$ hours

Speed of rail = 65 km/hr and speed of steamer = 25 km/hr

Using, speed = distance/time

For steamer, $$\frac{d}{t + 10} = 25$$

=> $$d = 25t + 250$$ --------------(i)

For rail, $$\frac{430 - d}{t} = 65$$

Substituting value of $$d$$ from equation (i), we get :

=> $$430 - (25t + 250) = 65t$$

=> $$430 - 250 = 65t + 25t = 90t$$

=> $$t = \frac{180}{90} = 2$$ hours

Substituting value of $$t$$ in equation (i), => $$d = (25 \times 2) + 250$$

= $$50 + 250 = 300$$ km

=> Ans - (B)