Question

A train crosses a signal post in X seconds. What is the length of the train?
(I) The train crosses a platform of 100 metres in Y seconds
(II) The train is running at the speed of 80 km/hr.

• A. Statement (I) alone is sufficient, but statement (II) alone is not sufficient.
• B. Statement (II) alone is sufficient, but statement (I) alone is not sufficient.
• C. Both statements together are sufficient, but neither statement alone is sufficient.
• D. Each statement alone is sufficient.

Answer 1

The correct option is D Each statement alone is sufficient.

Let the length of the train be 'L' m.
Speed of the train $=\frac{L}{X}$
(I) $\Rightarrow \frac{L}{X}=\frac{L+100}{Y}\Rightarrow L=\frac{100X}{Y-X}$
(II) $\Rightarrow L=80\times \frac{5}{18}X=\frac{200X}{9}$
Therefore, each statement alone is sufficient to answer the question.