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If the speed of a boat in still water is 20 km/hr and the speed of the current is 5 km/hr, then the time taken by the boat to travel 100 km with the current is :

A2 hours

B3 hours

C4 hours

D7 hours

Answer:

C. 4 hours

Read Explanation:

Solution:

Given:

Speed of Boat in Still water, BS = 20 km/hr

Speed of Current, Ss = 5 km/hr

Distance = 100 km

Calculation:

Rate downstream of boat Ds = Bs+Ss = (20 + 5) kmph = 25kmph

Required time =10025=4hours=\frac{100}{25}=4hours


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