A train covers a distance in 35 minutes . If the speed of the train is reduced by 10 km/hr, then the same distance is covered in 42 minutes . The distance is :
Answer & explanation
Correct answer: option 1
Distance = Speed × Time
Initial time taken = 35 minutes = \(\frac{35}{60}\) hr
Let distance = d km
Speed = \(\frac{D \; ×\; 60}{35}\) = \(\frac{12D}{7}\)
The speed of train reduced by 10 km/hr
New speed = \(\frac{12D}{7}\) - 10 = \(\frac{12D\;-\;70 }{7}\)
New time = 42 minutes
Distance ( D ) = \(\frac{12D\;-\;70 }{7}\) × \(\frac{42}{60}\)
2D = 70 km
D = 35 km