RRB Group-D Model Paper 16 with answers for online practice

Tips & Tricks
GIVEN:
The boat covers 15 km upstream in 5 hours and 24 km downstream in 4 hours
FORMULA USED:
If ‘D’ and ‘U’ are the Downstream and Upstream speeds:
Speed of boat in still water = (D + U)/2
Speed of current = (D – U)/2
CALCULATION:
According to the question,
Downstream speed = 24/4 = 6 km/h
Upstream speed = 15/5 = 3 km/h
∴ Speed of the Boat in still water = 1/2 × (6 + 3) = 4.5 km/h