## Time Speed and Distance Part 4

- A circular running path is 726 metres in circumference. Two men start from the same point and walk in opposite directions at 3.75 km/h and 4.5 km/h, respectively. When will they meet for the first time ?

(a) After 5.5 min (b) After 6.0 min (c) After 5.28 min (d) After 4.9 min

- A train after travelling 150 km meets with an accident and then proceeds with 3/5 of its former speed and arrives at its destination 8 h late. Had the accident occurred 360 km further, it would have reached the destination 4 h late. What is the total distance travelled by the train?

(a) 840 km (b) 960 km (c) 870 km (d) 1100 km

- A man swimming in a steam which flows 1 1 2 km/hr., finds that in a given time he can swim twice as far with the stream as he can against it. At what rate does he swim?

(a) 1 5 2 km/hr (b) 1 4 2 km/hr (c) 1 7 2 km/hr (d) None of these

- Two persons start from the opposite ends of a 90 km straight track and run to and fro between the two ends. The speed of first person is 30 m/s and the speed of other is 125/6 m/s. They continue their motion for 10 hours. How many times they pass each other?

(a) 10 (b) 9 (c) 12 (d) None of these

- A man starts from B to K, another from K to B at the same time. After passing each other they complete their journeys in 3 1 3 and 4 4 5 hours, respectively. Find the speed of the second man if the speed of the first is 12 km/hr.

(a) 12.5 kmph (b) 10 kmph (c) 12.66 kmph (d) 20 kmph

- A train 100 metres long moving at a speed of 50 km/hr. crosses a train 120 metres long coming from opposite direction in 6 sec. The speed of the second train is

(a) 60 km/hr. (b) 82 km/hr. (c) 70 km/hr. (d) 74 km/hr.

- A passenger sitting in a train of length 100 m, which is running with speed of 60 km/h passing through two bridges, notices that he crosses the first bridge and the second bridge in time intervals which are in the ratio of 7 : 4 respectively. If the length of first bridge be 280 m, then the length of second bridge is:

(a) 490 m (b) 220 m (c) 160 m (d) Can’t be determined

- A man can row a certain distance against the stream in six hours. However, he would take two hours less to cover the same distance with the current. If the speed of the current is 2 kmph, then what is the rowing speed in still water?

(a) 10 kmph (b) 12 kmph (c) 14 kmph (d) 8 kmph

- A boat, while going downstream in a river covered a distance of 50 mile at an average speed of 60 miles per hour. While returning, because of the water resistance, it took one hour fifteen minutes to cover the same distance . What was the average speed of the boat during the whole journey?

(a) 40 mph (b) 48 mph (c) 50 mph (d) 55 mph 40.

- Two trains, 130 m and 110 m long, are going in the same direction. The faster train takes one minute to pass the other completely. If they are moving in opposite directions, they pass each other completely in 3 seconds. Find the speed of each train.

(a) 38 m/sec, 36 m/sec (b) 42 m/sec, 38 m/sec (c) 36 m/sec, 42 m/sec (d) None of these

Answers and Solutions

- (c) Their relative speeds = (4.5 + 3.75) = 8.25 km/h

Distance = 726 metres = 726/1000km = 0. 726

Required time = 5.28min

- (c) The speeds of two persons is 108 km/h and 75 km/h. The first person covers 1080 km in 10 hours and thus he makes 12 rounds. Thus, he will pass over another person 12 times in any one of the direction.

- (b) 1st man ‘s speed2nt man ‘s speed= ab= 445313

2ns man’s speed is 10km/hr

- (b) Let speed of the second train = x km/hr. Relative speed of trains = (50 + x) km/hr. Distance travelled by trains = (100 + 120) = 220 metres

Distance = Speed × Time

(2201000) km = (50 + x)km/ hr (63600)h

50 + x = 132

X = 82 km/hr

- (c) Note here the length of the train in which passenger is travelling is not considered since we are concerned with the passenger instead of train. So, the length of the bridge will be directly proportional to the time taken by the passenger respectively.

t = Time

l = Length of bridge

Therefore t1t2= l1l2

X = 160m

- (a) If the rowing speed in still water be x kmph, and the distance by y km,

then yx-2= 6

y= 6(x-2) …(1) and,

yx+2 = 4

Y = 4 (x + 2) …(2)

6 (x – 2) = 4 (x + 2)

x = 10 kmph

- (b) Time taken by the boat during downstream journey = 5060h = 56h

Time taken by the boat in upstream journey = 54h

Average speed = 25056 + 54 =1002450= 48mph

- (b) Let the Speed of faster train be x and speed of slower train be y.

Now, when both the train move in same direction their relative speed = x – y

Now, total distance covered = 130 + 110 = 240

Now, distance = speed × time

240 = ( x– y) × 60 ( 1min = 60sec)

x – y = 4 …(1)

When the trains move in opposite direction then their relative speed = x + y

240 = ( x + y) × 3

80 = x + y …(2)

on solving eqs (1) and (2),

we get x = 42 m/sec and y = 38 m/sec