Question
A boat takes 2 hours 20 minutes to cover 140 km
downstream and 2.5 hours to cover 75 km upstream. If the boat covers 'y' km upstream and '2y' km downstream in 8 hours, find the value of 1.5y .Solution
ATQ,
Downstream speed = (140 ÷ 2.33) = 60 km/h Upstream speed = (75 ÷ 2.5) = 30 km/h Now, (y ÷ 30) + (2y ÷ 60) = 8 ⇒ (2y + 2y) ÷ 60 = 8 ⇒ 4y = 480 ⇒ y = 120 Required value = 1.5 × 120 = 180
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