1. A travel bus normally reaches its destination at 60 kmph in 20 hours. Find the speed of that travel bus at which it travels to reduce the time by 5 hours?

A. 80 kmph B. 60 kmph C. 50 kmph D. 40 kmph

Answer Answer: Option A Explanation: 60*20 = x * 15
x = 80 kmph

3. A truck travelled to a place Q from P, The first 50 km at 10 kmph faster than the usual speed, but it returned the same distance at 10 kmph slower than usual speed. If the total time taken by the truck is 12 hours, then how many hours will travel at the faster speed?

A. 8 hours B. 6 hours C. 2 hours D. 3 hours

Answer Answer: Option C Explanation: Total time taken,
{50/(x - 10)} + 50/(x+10)} = 12 hours
By solving the equation, we get
x = 15
time is taken by the truck at faster speed = 50/(15+10) = 2 hours.

4. There is a road beside a river.Two friends started from a place A moved to a temple situated at another place B and then returned to A again.One of them moves on a cycle at a speed of 12 km/hr while the other sails on a boat at a speed of 10 km/hr.If the river flows at the speed of 4 km/hr which of the two friends will return to place A first?

A. 7 km/hr B. 8 km/hr C. 8.4 km/hr D. 9.2 km/hr

Answer Answer: Option C Explanation: Clearly the cyclist moves both ways at a speed of 12 km/hr
so average speed of the cyclist = 12 km/hr
The boat sailor moves downstream at ( 10+4) i.e, 14 km/hr and upstream at (10-4) i.e, 6 km/hr
So average speed of the boat sailor =(2*14*6/14+6) km/hr = 42/5 km/hr = 8.4 km/hr
since the average speed of the cyclist is greater he will return to A first.