A boat takes 60 % more time to cover a certain distance in upstream than downstream. If speed of current is 9 km/hr., then in how much time it will go 504 km in downstream?
Answer & explanation
Correct answer: option 1
60% = \(\frac{3}{5}\)
Speed ratio :-
⇒ Downstream : Upstream = 8 : 5
⇒ Boat : Current = \(\frac{8+5}{2}\) : \(\frac{8-5}{2}\) = \(\frac{13}{2}\) : \(\frac{3}{2}\)
⇒ Speed of current = \(\frac{3}{2}\)R = 9 km/hr (given)
1R = 6
⇒ So, Downstream speed = 8 × 6 = 48 km/hr
Time to cover 504 km downstream = \(\frac{504}{48}\) = 10.5 hr.