Previous Year Questions

Let two boats A and B covers 240 km and 340 km downstream distance in a hours and b hours respectively. The respective ratio of downstream of boat A to the speed of boat B in still water is c respectively. Stream is flowing with speed d km/hr. Then,

Speed of boat B in still water = 24 km/hr

Difference between upstream speed of both boats = difference between downstream speed of both boats = difference between speed of both boats in still water

Then, speed of boat A in still water = 24 - 2 = 22 km/hr

Speed of stream = d = 22 * 100/(100 + 120) = 10 km/hr => d = 10

Then, upstream speed of boat A = 22 - 10 = 12 km/hr

Downstream speed of boat A = 22 + 10 = 32 km/hr

Upstream speed of boat B = 24 - 10 = 14 km/hr

Downstream speed of boat B = 24 + 10 = 34 km/hr

Then, a = 240/32 => a = 7.5

b = 340/34 => b = 10

c = 32: 24 => c = 4: 3