Question
Ratio of downstream and upstream speed of a boat is 5:2.
If the speed of stream is 3 km/h, find the distance travelled by boat in downstream in 2 hours.Solution
Let the speed of boat be x km/h. => (x + 3)/(x – 3) = 5/2 ⇒ 2x + 6 = 5x – 15 ⇒ 3x = 21 ⇒ x = 7 Downstream speed = 7 + 3 = 10 km/h Required distance = 10 × 2 = 20 km
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