Q 26. A motor boat covers a certain distance downstream in a river in

1.	Q 26. A motor boat covers a certain distance downstream in a river in 5 hours. It coversthe same distance upstream in 6 hours. The speed of water is 2km/hr. Find the speed ofthe boat in still water.
Answer» Let, the speed of boat in still water be x kmph Therefore, speed of boat in downstream is (x+5) kmph And, speed of boat in upstream is (x-5) kmph Now, in downstream the boat covers distance in 1/2 hr (30m) =(x+5)/2 km And, in upstream the boat covers distance in 3/4 hr (45m) = (x-5).3/4km As both the distances are same,(x+5)/2= (x-5).3/4 i.e., 2.(x+5)/2.2 = (x-5).3/4 i.e., 10+2x = 3x-15 i.e., 2x-3x = -15–10 i.e.,-x=-25 i.e., x=25 Hence, the speed of boat in still water is 25 kmph

Q 26. A motor boat covers a certain distance downstream in a river in 5 hours. It coversthe same distance upstream in 6 hours. The speed of water is 2km/hr. Find the speed ofthe boat in still water.

Answer»

Let, the speed of boat in still water be x kmph

Therefore, speed of boat in downstream is (x+5) kmph

And, speed of boat in upstream is (x-5) kmph

Now, in downstream the boat covers distance in 1/2 hr (30m) =(x+5)/2 km

And, in upstream the boat covers distance in 3/4 hr (45m) = (x-5).3/4km

As both the distances are same,(x+5)/2= (x-5).3/4

i.e., 2.(x+5)/2.2 = (x-5).3/4

i.e., 10+2x = 3x-15

i.e., 2x-3x = -15–10

i.e.,-x=-25

i.e., x=25

Hence, the speed of boat in still water is 25 kmph