DEFINITION: The speed of a moving body is the distance travelled by it in unit time.
Results
#1. Find the time taken to cover a distance of 124 km by a train moving at 54 km/h.
Find the time taken to cover a distance of 124 km by a train moving at 54 km/h.
Time = distance/ speed
= 124/ 45 hours
= 2 34/45 hours
=2 plus (34/45*60) min.
2 hours 45 min.
#2. A man is walking at a speed of 10 km per hour. After every kilometre, he takes rest for 5 min. How much time will be take to cover a distance of 5 km?
A man is walking at a speed of 10 km per hour. After every kilometre, he takes rest for 5 min. How much time will be take to cover a distance of 5 km?
Rest time = Number of test * time for each rest
= 4 * 5 = 20 min.
Total time to cover 5 km = (5/10 * 60)min.
30 20 min.
= 50 min.
#3. A person crosses a 600 m long street in 5 minutes. What is his speed in km per hour?
A person crosses a 600 m long street in 5 minutes. What is his speed in km per hour?
Speed = (600/5*60) m/sec
= ( 2*18/5)km/hr
= 7.2 km/hr
#4. A man walking at the rate of 5 km per hours crosses a bridge in 15 minute. The length of the bridge (in metres) is :
A man walking at the rate of 5 km per hours crosses a bridge in 15 minute. The length of the bridge (in metres) is :
Speed = ( 5*5/18)m per sec.
= 25/18 m per sec
distance covered in 15 min. = (25/18*15*60)m
= 1250 m
#5. How long will a boy take to run round a square field of side 35 metres, If he runs at the rate of 9 km per hour
How long will a boy take to run round a square field of side 35 metres, If he runs at the rate of 9 km per hour
Speed = 9 km per hr= (9* 5/18) m per sec.
= 5/2 m per sec
Distance = (35* 4) m = 140 m
Time taken = (140 *2/5) m
= 56 sec
#6. A truck cover a distance of 550 meter in 1 minutes whereas a bus cover a distance of 33 Kms in 45 minutes . The ratio of their speeds is :
A truck cover a distance of 550 meter in 1 minutes whereas a bus cover a distance of 33 Kms in 45 minutes . The ratio of their speeds is :
Ratio of speeds =( 550/6*18/5 ):( 33/45*60 )
= 33 : 44
=3 : 4
#7. A running at the speed of 180 Kmph . what distance will it cover in 15 seconds ?
A running at the speed of 180 Kmph . what distance will it cover in 15 seconds ?
Speed = 180 Kmph =(180*5/18) m per sec
=30 m per sec
Distance covered in 15 sec = (30*15) m
=450 m
#8. Sound is said to travel in air about 1100 feet per second . A man hears the axe striking the tree , 11/5 second after he sees it strike the tree . How far is the man from the wood chopper :
Sound is said to travel in air about 1100 feet per second . A man hears the axe striking the tree , 11/5 second after he sees it strike the tree . How far is the man from the wood chopper :
Distance = (1100 * 11/5 ) feet
= 2420 feet
#9. The speed of car increases by 2 Kms after every one hour . if the distance travelled in the first one hour was 35 Kms ,What was the total distance travelled in 12 hours ?
The speed of car increases by 2 Kms after every one hour . if the distance travelled in the first one hour was 35 Kms ,What was the total distance travelled in 12 hours ?
total distance travelled in 12 hours=( 35 plus 37 plus 39 plus ….. upto 12 terms )
This is an A.P with first term ,a = 35 , number of term , n = 12 , common difference , d = 2
Required distance = 12/2(2*35 plus (12 – 1)*2)
= 6 (70 plus 22 )
552 Km
#10. An aeroplane cover a certain .distance at speed of 240 Kmph is 5 hours . To cover the same distance in 1 2/3 hours , it must travel at a speed of :
An aeroplane cover a certain .distance at speed of 240 Kmph is 5 hours . To cover the same distance in 1 2/3 hours , it must travel at a speed of :
Distance = ( 240*5) Km
=1200 Km
required speed = (1200*3/5)Km per hr
=720 Km per hr
#11. A is faster than B. A and B each walk 24 Km . The sun of their speed is 7 Km per hr and the same of time taken by then is 14 hours . then , A's speed is equal to
A is faster than B. A and B each walk 24 Km . The sun of their speed is 7 Km per hr and the same of time taken by then is 14 hours . then , A’s speed is equal to:
A’s speed = x km /hr. then B speed = ( 7 – x ) Km / h.
24/x plus 24 / (7 – x ) = 14
24 ( 7 – x ) plus 24 x
=14 x ( 7 – x )
14 x² – 98 x plus 168 = 0
x² – 7 x plus 12 = 0
( x – 3 ) ( x – 4 ) = 0
x = 3 or x 4
#12. A person travel from P and Q at a speed of 40 Kmph and returns by increasing his speed by 50% . What is his average speed for both the tripe ?
A person travel from P and Q at a speed of 40 Kmph and returns by increasing his speed by 50% . What is his average speed for both the tripe ?
Speed on return trip = 150% of 404 = 60 Kmph
Average speed = (2*40*20/40 plus 60)Km/hr
= (4800/100)km/hr
= 48 km/hr
#13. A car travelling with 5/7 of its actual speed covers 42 Km in 1 hr 40 min 48 sec . Find the actual speed of the car .
A car travelling with 5/7 of its actual speed covers 42 Km in 1 hr 40 min 48 sec . Find the actual speed of the car .
Time taken = 1 hr 40 min 48 sec = 1 hr 40 4/5 min
=1 51/75 hrs
=126 /75 hrs
Let , the actual speed be x Km /hr
5/7x *126/75 = 42
x = (42 * 7 * 75/5 * 126 )
35 Km/hr
#14. A man can reach a certain place in 30 hr . If the reduce his speed by 1/15 th, he goes 10 km less in that time find his speed ,?
A man can reach a certain place in 30 hr . If the reduce his speed by 1/15 th, he goes 10 km less in that time find his speed ,?
let the speed be x km/hr
then 30 x – 30 * 14 / 15x = 10
2x = 10
x= 5km/hr
#15. Walking 6/7th of is usual speed, a man is 12 minutes too late. The usual time taken by him cover that distance is :
Walking 6/7th of is usual speed, a man is 12 minutes too late. The usual time taken by him cover that distance is :
New speed = 6/7 of usual speed
new time = 7/6 of usual time
(7/6 of usual time ) – ( usual time) = 1/5 hr
1/6 of usual time = 1/5 hr
usual time = 6/5
= 1 hr 12 min
#16. A man on tour travels first 160 km / hr and the next 160 km at 80 km/ hr.The average speed for the first 320 km of the tour is :
A man on tour travels first 160 km / hr and the next 160 km at 80 km/ hr.The average speed for the first 320 km of the tour is :
Total time taken =(160/ 64 plus 160/8)hrs
= 9/2 hrs
Average speed = (320*2/9)km/hr
71.11 km/hr.
#17. An athlete runs 200 metres race in 24 seconds. His speed is :
An athlete runs 200 metres race in 24 seconds. His speed is :
Speed= 200/24 m/sec =25 m/sec
=(25/3*18/5)km/hr
=30 km/hr
#18. How many minutes does Aditya take to cover a distance of 400 m, If he runs at speed of 20 km/hr?
How many minutes does Aditya take to cover a distance of 400 m, If he runs at speed of 20 km/hr?
Aditya’ s speed = 20 km/hr =(20*5/18)m/sec
=50/9 m/sec
Time taken to cover 400m= (400*9/50)sec
=72 sec= 1 12/60 min
= 1 ¹/₅ min
#19. Find the distance covered by a man walking for 12 min. at a speed of 3.5 km/hr
Find the distance covered by a man walking for 12 min. at a speed of 3.5 km/hr
Distance = speed * time
= 3.5*12/60
[12 minutes = 12/60 hours]
7/10 km
=700 m
#20. Find the distance covered by a car moving at 20 metres per second for 3 hours.
Find the distance covered by a car moving at 20 metres per second for 3 hours.
1 metre per second= 18/5 km/hr
distance = speed * time
=20*(18/5)*3 km
216 km