Question

a man covers 118km by a boat travelling 4 hours downstream and 3 hours upstream.He also covered 130km travelling 5 hours downstream and 2 hours upstream.Find the speed of boat in still water and the speed of water​

Answer 1

Answer:

Speed of water= 6 km/hour

Speed of boat = 16 km/hour

Explanation:

Let , Speed of boat in still water = x km /hour

Speed of water = y km/hour

Speed in downstream = (x+y) km/hour

Speed in upstream = (x-y) km/hour

In 1st conditions,

4(x+y) + 3(x-y) = 118

or, 7x +y = 118 ----->(I)

In 2nd conditions,

5(x+y) + 2(x-y) =130 -----> 130

or, 7x +3y = 130 ------> (ii)

Substruction, equation (I) from equation (ii)

2y = (130-118)=12

or, y= 12/2 = 6

Now , we put y=6 in equation I , we get

7x + 6 = 118

or, 7x = 118- 6 =112

or, x= 112/7 = 16

Speed of Boat in still water = 16 km/ hour

Speed of Water = 6 km/hour