Here’s and example of a **SMART MATH** problem for **TIME SPEED DISTANCE.**

**Problem**

**Problem**

Two trains travel in the same direction at 50 and 32 km/hr. A man in the slower train observes that it takes 15 seconds for the faster train to completely pass him. What is the length of the slower train?

- 75 meters
- 100 meters
- 160 meters
- 200 meters
- 250 meters

**The Usual Method**

[contentblock id=google-adsense-post]

Relative speed of the two trains = 50 – 32 = 18 km/hr.

18 km/hr = = 5 m/s

Hence, length of the slower train = 5 x 15 = 75 meters

**(Ans: 1)**

*Estimated Time to arrive at the answer = 30 seconds.*

**Using Technique**

[contentblock id=google-adsense-post]

Since Distance = speed x time,

The length of the train should be a multiple of both the speed and the time.

Time taken is known as 15 seconds. Hence, length of the slower train should be a multiple of 15. The only option which is a multiple of 15 is option ‘1’.

**(Ans: 1)**

*Estimated Time to arrive at the answer = 5 seconds.*

[starrater tpl=10]

[contentblock id=smartmath-blockquote]

## One reply on “[Smart Math] Time Speed Distance Problem 5”

This question seems to be wrong.

The answer that has been calculated is for the length of faster train, not for the slower train