A car covers four successive 7km distances at speeds of 10 km/hour, 20 km/hour, 30 km/hour and 60 km/hour respectively. Its average speed over this distance is

• 30 km/hour

• 20 km/hour

• 60 km/hour

• 60 km/hour

42.

If a man walks at the rate of 5 km/hour, he misses a train by 7 minutes. However if he walks at the rate of 6 km/hour, he reaches the station 5 minutes before the arrival of the train. The distance covered by him to reach the station is

• 6 km

• 7 km

• 6.25 km

• 6.25 km

A man starts from a place P and reaches the place Q in 7 hours. He travels  of the distance at 10 km/hour and the remaining distance at 12 km/hour. The distance between P and Q is

• 72 km

• 90 km

• 80 km

• 80 km

A car can finish a certain journey in 10 hours at the speed of 42 kmph. In order to cover the same distance in 7 hours, the speed of the car (km/h) must be increased by

• 12

• 15

• 18

• 18

On a river, Q is the mid-point between two points P and R on the same bank of the river. A boat can go from P to Q and back in 12 hours, and from P to R in 16 hours 40 minutes. How long would it take to go from R to P?

• 3¹⁄₃ hours

• 5 hours

• 3²⁄₆ hours

• 7¹⁄₃ hours

A man travels for 14 hours 40 min. He covers half of the journey by train at the rate of 60 km/hr and rest half by road at the rate of 50 km/hr. The distance travelled by him is

• 720 km

• 800 km

• 960 km

• 960 km

Sound travels 330 m in a second. When the sound follows the flash of lightning after 10 sec, the thunder cloud will be at a distance of

• 1300 m

• 2000 m

• 3650 m

• 3650 m

A man travelled a distance of 61 km in 9 hours, partly by walking at a speed of 4 km/hr and partly on bicycle at speed of 9 km/hr. The distance covered by walking is

• 16 km

• 12 km

• 15 km

• 15 km

The distance between two places A and B is 60 km. Two cars start at the same time from A and B, travelling at a speed of 35 km/hr and 25 km/hr respectively. If the cars run in the same direction, then they will meet after (in hours):

• 6.5

• 6.2

• 6

• 6

Sound travels at 330 m/sec. The distance (in km) of a thunder cloud when its sound follows the flash after 10 sec is

• 0.33 km

• 3.3 km

• 33 km

• 33.3 km