Multiple choice

If a boat can travel a certain distance downstream in t1 hours and the same distance upstream in t2 hours then what is the speed of the current if the speed of the boat is 10 kmph. It is given that t2 is 50% more than that of t1?

  1. 1.5 kmph

  2. 2 kmph

  3. 2.5 kmph

  4. 3 kmph
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Let current speed be x. Downstream speed = 10+x, upstream = 10-x. Given t2 = 1.5*t1, so (d/(10-x)) = 1.5*(d/(10+x)). Solving: 10+x = 1.5(10-x), giving x = 2 kmph.

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