Discussion Forum



Each of the questions given below consists of two statements numbered I and II given below it. Please read the questions carefully and decide whether the data provided in the statement(s) is / are sufficient to answer the given question.

1)

What is the speed of the train?

I. $280$ metres long train crosses a signal pole in $18$ seconds

II. $280$ metres long train crosses a platform in $45$ seconds.


A) I alone sufficient while II alone not sufficient to answer

B) II alone sufficient while I alone not sufficient to answer

C) Either I or II alone sufficient to answer

D) Both I and II are not sufficient to answer

E) Both I and II are necessary to answer

Answer:

Option A

Explanation:

Speed = Length of the train / Time taken to cross the pole $=\frac{280}{18}$ m/s $=\frac{140}{9}$ m/s.

$\therefore$ I alone gives the answer.

Time taken to cross the platform = (Length of train + Length of platform) / Speed of the train

$\Rightarrow$ Speed $=\frac{(280+p)}{45}$ m/s.

But, p = length of platform, is not given.

$\therefore$ II is not sufficient to give the answer.

$\therefore$ The correct answer is (A).