**Problem 1:** A boat can cover 40 km upstream and 60 km downstream together in 13 hours. Also, it can cover 50 km upstream and 72 km downstream together in 16 hours. What is the speed of the boat in still water?

Solution:

Speed of the boat = x km/h

Speed of the current = y km/h

Downstream=x+y km/h

Upstream =x-y km/h

Solving this will take much time

Shortcut

Up DO T

(40 60 13)*5

(50 72 16)*4

200 300 65

200 288 64

Downstream = 300-288=12km/h

65-64=1

12———>1hr

60———->?

72———->?

13-5=8

Upstream=5km/h

Speed of the boat still in water=km/h

**Problem 2:** A boat can cover 20 km upstream and 32 km downstream together in 3 hours. Also, it can cover 40 km upstream and 48 km downstream together in 5 and half hours. What is the speed of the current?

Solution:

Up DO T

(20 32 3)*2

40 48

40 64 6

40 48

64-48=16 6 – =0.5

16———->0.5

1————–>? 32 is downstream

64———->?

6-2=4

is upstream

Speed of the current is =