Multiple choice

Passage

What is the speed of stream?

(A) Sum of time taken by a boat in upstream and downstream is 27 hours to cover distance 270 km in each. (B) Speed of boat in downstream is 45 km/h. (C) Boat cover 90 km in 7 hr, while rowing in upstream

  1. (a)Either A and B or B and C Are sufficient to answer the question

  2. (b) Either A and B or A and C Are sufficient to answer the question

  3. (c) Either A and C or B and C Are sufficient to answer the question

  4. (d) Any two statements are sufficient to answer the question

  5. (e) Either only A or B and C together are sufficient to answer the question
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Let boat speed be B and stream speed be S. (A) 270/(B-S) + 270/(B+S) = 27. (B) B+S = 45. (C) 90/(B-S) = 7. Using C, B-S = 90/7. With B+S = 45, we can solve for S. Using A and B, we can also solve for S. Any two statements provide enough info to solve for B and S.

AI explanation

Taking statements A and B, we have the sum of upstream and downstream times as 27 hours for 270 km, and the downstream speed is 45 km/h, which easily allows us to calculate the upstream speed and subsequently the stream speed. Taking statements A and C, the upstream speed is 90/7 km/h, and combined with the total time of 27 hours, we can find the downstream speed to determine the stream speed. Taking statements B and C, we directly get the downstream speed of 45 km/h and upstream speed of 90/7 km/h, so the stream speed is half their difference, meaning any two statements are sufficient.

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