Question

A bus runs at 80 km per hour and reaches its destination 40 minutes late. If it had moved at a speed of 90 kilometers per hour, it would have reached only 8 minutes late. The right time in which the bus completes it's journey is:

A. 248 minutes

B. 340 minutes

C. 212 minutes

D. 315 minutes

1. C
2. B
3. A
4. D

Answer 1

Correct Answer - Option 3 : A

Given:

In 1st case when bus runs at 80km per hour it reaches its destination 40 minutes late

In 2nd case when bus runs at 90km per hour it reaches its destination only 8 minutes late.

Formula used:

Time = Distance/speed

Calculation:

Let the correct time for the train to complete the journey is X minutes.

Then the train cover distance in X + 40 minutes at speed 80 km per hour

⇒ 80 × (X + 40)/60  

Now the train cover X + 8 minutes at speed 90km per hour 

⇒ 90 × (X + 8)/60

Now,  

80 × (X + 40)/60 = 90 × (X + 8)/60 ​

⇒ 80X + 3200 = 90X + 720

⇒ 10X = 2480

⇒ X = 248

∴ The correct answer is 248 min.