## Time, Speed and Distance part 1

- An aeroplane flies along the four sides of a square at the speeds of 200, 400, 600 and 800 km/h. Find the average speed of the plane around the field.

(a) 384 km/h (b) 370 km/h (c) 368 km/h (d) None of these

- A monkey ascends a greased pole 12 metres high. He ascends 2 metres in first minute and slips down 1 metre in the alternate minute. In which minute, he reaches the top ?

(a) 21st (b) 22nd (c) 23rd (d) 24th

- A man walks a certain distance and rides back in 1 6 h. 4 He can walk both ways in 3 7 h. 4 How long it would take to ride both ways ?

(a) 5 hours (b) 1 4 hours 2 (c) 3 4 hours 4 (d) 6 hours

- There are 20 poles with a constant distance between each pole. A car takes 24 seconds to reach the 12th pole . How much time will it take to reach the last pole?

(a) 25.25 s (b) 17.45 s (c) 35.75 s (d) 41.45 s

- A man is walking at a speed of 10 km per hour. After every kilometre, he takes rest for 5 minutes. How much time will he take to cover a distance of 5 kilometres?

(a) 48 min. (b) 50 min. (c) 45 min. (d) 55 min.

- On a journey across Bombay, a tourist bus averages 10 km/h for 20% of the distance, 30 km/h for 60% of it and 20 km/h for the remainder. The average speed for the whole journey was (a) 10 km/h (b) 30 km/h (c) 5 km/h (d) 20 km/h

- In a 800 m race around a stadium having the circumference of 200 m, the top runner meets the last runner on the 5th minute of the race. If the top runner runs at twice the speed of the last runner, what is the time taken by the top runner to finish the race ?

(a) 20 min (b) 15 min (c) 10 min (d) 5 min

- A man walks half of the journey at 4 km/h by cycle does one third of journey at 12 km/h and rides the remainder journey in a horse cart at 9 km/h, thus completing the whole journey in 6 hours and 12 minutes. The length of the journey is

(a) 36 km (b) 1332 km 67 (c) 40 km (d) 28 km

- A train does a journey without stoppage in 8 hours, if it had travelled 5 km/h faster, it would have done the journey in 6 hours 40 minutes. Find its original speed.

(a) 25 km/h (b) 40 km/h (c) 45 km/h (d) 36.5 km/h

- A train leaves station X at 5 a.m. and reaches station Y at 9 a.m. Another train leaves station Y at 7 a.m. and reaches station X at 10: 30 a.m. At what time do the two trains cross each other ?

(a) 7 : 36 am (b) 7 : 56 am (c) 8 : 36 am (d) 8 : 56 am

Answers and solutions

- (a) Let each side of the square be x km and let the average speed of the plane around the field be y km/h.

Then, Average speed = 384 km/h.

- (a) In 2 minutes, he ascends = 1 metre

10 metres, he ascends in 20 minutes.

He reaches the top in 21st minute.

- (c) We know that, the relation in time taken with two different modes of transport is

t(walk both) + t(ride both) = 2 (twalk + t ride)

314 + t (ride both) = 2 254

t(ride both) = 434hrs

- (d) Let the distance between each pole be x m.

Then, the distance up to 12th pole = 11 x m

Speed = 11x24 m/s

Time taken to covers the total distance of 19x = 41.45s

- (b) Rest time = Number of rest × Time for each rest

= 4 × 5 = 20 minutes

Total time to cover 5 km

(510 60) minutes + 20 minutes = 50 minutes.

- (d) Let the average speed be x km/h.

and total distance be y km.

Then, 0.210y + 0.630y + 0.220y = yx

X = 20km/hr

- (c) After 5 minutes (before meeting), the top runner covers 2 rounds i.e., 400 m and the last runner covers 1 round i.e., 200 m. T

op runner covers 800 m race in 10 minutes.

- (a) Let the length of the journey =x km.

Journey rides by horse cart = x(1- 12 – 13) = 16x km

x= 36km

- (a) Let original speed = S km/h

Here, distance to be covered is constant

S 8 = (S + 5)(203)

S = 25km/hr

- (b) Let the distance between X and Y be x km.

Then, the speed of A is x4 km/h and that of B is 2x7 km/h.

Thus, both of them meet at 7 : 56 a.m.