Multiple choice

A boat can travel (\frac{3}{4}) km in downstream in (\frac{4}{5}) hour and return in upstream in (\frac{6}{5}) hour find the ratio of the speed of the boat in still water and speed of current ?

  1. 3 : 2

  2. 5 : 1

  3. 4 : 5

  4. 5 : 4

  5. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Downstream speed = (3/4)÷(4/5) = 15/16 km/h. Upstream speed = (3/4)÷(6/5) = 5/8 km/h. Let boat speed = b, current speed = c. Then b+c = 15/16 and b-c = 5/8 = 10/16. Adding: 2b = 25/16, so b = 25/32. Then c = 15/16 - 25/32 = 5/32. Ratio b:c = 25/32 : 5/32 = 25:5 = 5:1.

Keep practicing — related questions