Direction: Each of the questions below consists of a question and three statements numbered I, II and III given below it. You have to study the questions and decide the data in which of the statements are sufficient to answer the questions.
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What is the speed of the train ‘A’?
I. Train A crosses 200-metre-long train B running in opposite direction in 20 seconds.
II. Speed of the train B is 60 Km/h.
III. Length of train A is twice that of train B.
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- I and II only
- II and III only
- I and III only
- All, I II and III
- Question cannot be answered even within formation in all three statements.
Correct Option: D
As per given above question , we have
I.Length of train B = 200 m , Time = 20 seconds
| ∴ speed of train A + speed of train B = | Distance of train A + Length of train B |
| Time |
| ⇒ VA + VB = | DA + 200 |
| 20 |
II. Speed of train B ( VB ) = 60 Km/h
III. Length of train A ( DA ) = 2 x Length of train B = 2 x 200 = 400 m.
Putting the values of II and III in I, we get the value of VA = 48 Km/h.
| speed of train A + 60 = | ( 400 + 200 ) | x | 18 |
| 20 | 5 |
| ⇒ VA + 60 = | 120 | x 9 |
| 10 |
⇒ VA + 60 = 12 x 9 = 108 ⇒ VA = 108 - 60 = 48 km//h.
