# Aptitude - Races and Games - Discussion

Discussion Forum : Races and Games - General Questions (Q.No. 7)

7.

In 100 m race, A covers the distance in 36 seconds and B in 45 seconds. In this race A beats B by:

Answer: Option

Explanation:

Distance covered by B in 9 sec. = | 100 | x 9 | m | = 20 m. | |

45 |

A beats B by 20 metres.

Discussion:

13 comments Page 1 of 2.
Sheth said:
4 years ago

Time ratio = 36:45 = 4:5.

Speed ratio = 5:4.

when A complete 5 B complete 4.

A complete 100 B complete 100*4/5 = 80m so A beat B by 20m.

Speed ratio = 5:4.

when A complete 5 B complete 4.

A complete 100 B complete 100*4/5 = 80m so A beat B by 20m.

(2)

Sana said:
7 years ago

Common time difference between A and B is =(45-36)=9sec.

Now, B travel distance 100m in 45sec.

So

45sec ----------> 100m

9sec ------------> (9/45)*100=20m.

This 20m is actual distance between A and B or A beat by B in 20m .

Now, B travel distance 100m in 45sec.

So

45sec ----------> 100m

9sec ------------> (9/45)*100=20m.

This 20m is actual distance between A and B or A beat by B in 20m .

(1)

Madhu said:
3 years ago

Lets time ratio is =

A : B A : B

36:45 => 4:5.

The speed ratio is;

A : B

5 : 4.

If a completes 100 with 5 units of speed, then B completes 80 with 4 units of speed.

A : B A : B

36:45 => 4:5.

The speed ratio is;

A : B

5 : 4.

If a completes 100 with 5 units of speed, then B completes 80 with 4 units of speed.

(1)

Muneer said:
1 decade ago

Why we are taking 45 in the solution?

Gowthami said:
1 decade ago

A beats=36sec

B beats=45sec

so 36----45

then 1 part=45/36=5/4

B covers A in 100m race=(4/5)*100=80m

so A beats B by=(total distance)100-B covers(80)

20m faster than B

B beats=45sec

so 36----45

then 1 part=45/36=5/4

B covers A in 100m race=(4/5)*100=80m

so A beats B by=(total distance)100-B covers(80)

20m faster than B

Himanshu Singla said:
1 decade ago

Here it is given that A can cover 100m in 36 sec and B in 45 sec. So when A reaches finish point B still has 9 sec left of his time to reach the final point. In this time he can cover the remaining distance by which he has been beaten.

In 45sec B can travel 100m.

In 1sec ------------- 100/45.

In 9 sec ------------ (100/45) *9=20 Answer.

HOPE you UNDERSTAND. Please clarify if am wrong.

In 45sec B can travel 100m.

In 1sec ------------- 100/45.

In 9 sec ------------ (100/45) *9=20 Answer.

HOPE you UNDERSTAND. Please clarify if am wrong.

Marimuthu said:
1 decade ago

In 36 seconds B covers (100/45)*36 = 80 meters.

In 36 seconds A covers 100 meters.

So A beat B by 20 meters.

In 36 seconds A covers 100 meters.

So A beat B by 20 meters.

Mridul Chakraborty said:
1 decade ago

Detailed solution for easier interpretation :

Speed of A = 100 (distance)/36 (Time) = 2.78 m/s.

Speed of B = 100(distance)/45(Time) = 2.22 m/s.

Difference in speed between A & B = 0.56 m/s < i.e. 2.78-2.22 m/s>

Hence in 36 seconds in which A finishes the race, B will cover 2.22*36 = 80 meters.

So A finishes the race 20m ahead of B.

Speed of A = 100 (distance)/36 (Time) = 2.78 m/s.

Speed of B = 100(distance)/45(Time) = 2.22 m/s.

Difference in speed between A & B = 0.56 m/s < i.e. 2.78-2.22 m/s>

Hence in 36 seconds in which A finishes the race, B will cover 2.22*36 = 80 meters.

So A finishes the race 20m ahead of B.

NoName said:
9 years ago

A 1sec - (100/36) m.

B 1sec - (100/45) m.

1sec - A is ahead by (100/36-100/45) = 5/9 m.

So, in 36s A is ahead by (5/9*36) = 20 m.

B 1sec - (100/45) m.

1sec - A is ahead by (100/36-100/45) = 5/9 m.

So, in 36s A is ahead by (5/9*36) = 20 m.

Santhosh said:
9 years ago

36/45*100 = 80.

100-80 = 20.

100-80 = 20.

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