Question

The problem below consists of a question and two statements numbered 1 & 2. You have to decide whether the data provided in the statements are sufficient to answer the question. Rahim is riding upstream on a boat, from point A to B, at a constant speed. The distance from A to B is 30 km. One minute after Rahim leaves from point A, a speedboat starts from point A to go to point B. It crosses Rahim’s boat after 4 minutes. If the speed of the speedboat is constant from A to B, what is Rahim’s speed in still water? 1. The speed of the speedboat in still water is 30 km/hour. 2. Rahim takes three hours to reach point B from point A.

• A. Statement 1 alone is sufficient to answer the question, but statement 2 alone is not sufficient
• B. Statement 2 alone is sufficient to answer the question, but statement 1 alone is not sufficient
• C. Each statement alone is sufficient
• D. Both statements together are sufficient, but neither of them alone is sufficient
• E. Statements 1 & 2 together are not sufficient

Answer 1

Answer: (D)

Both statements together are sufficient, but neither of them alone is sufficient

Answer 2

Let the speed of Rahim and Speed boat in still water be 'R' kmph and 'S' kmph, respectively. Speed of the water is W kmph. Let the speedboat cross Rahim at point X.
Given that:
AX/R-W = 5/60, Ax/S-W = 4/60
Thus,
W = 5R - 4S .….(1)
Statement I:
S = 30 km/hr …..(2),
As W or AX is not known, I is not sufficient to answer this question.
Statement II:
BA/R+W = 3 km/hr, or …..(3)
As S or AX is not known, II is not sufficient to answer this question.
Both the statements:
Substituting (3) and (2) in (1)
10 - R = 5R - 4 x 30
or, R = 65/3
Hence, option D is the correct answer.