Aptitude - Races and Games - Discussion

Discussion Forum : Races and Games - General Questions (Q.No. 3)
3.
In a 500 m race, the ratio of the speeds of two contestants A and B is 3 : 4. A has a start of 140 m. Then, A wins by:
60 m
40 m
20 m
10 m
Answer: Option
Explanation:

To reach the winning post A will have to cover a distance of (500 - 140)m, i.e., 360 m.

While A covers 3 m, B covers 4 m.

While A covers 360 m, B covers 4 x 360 m = 480 m.
3

Thus, when A reaches the winning post, B covers 480 m and therefore remains 20 m behind.

A wins by 20 m.

Discussion:
14 comments Page 1 of 2.

Yadu said:   3 years ago
How come we take 3 as 3m and 4 as 4m If time is not a constant here?

Anyone, explain to me.

ANUPCHERRY said:   4 years ago
A : B =140M.
3X + 4X =7X,
140/7 = 20M.
(8)

BKD said:   4 years ago
3/4 = (500-140)/x.
x = 480.

Thus, In 500 m race, A gives B by 20m i.e.500-480.
(1)

Anand said:   5 years ago
Here is the simplest method,

Speed ratio is 3:4 SO let consider 3m & 4m for both A & B.
A travels 360 and B travels 500.
This means A takes 120 seconds and B takes 125 seconds.
5 seconds more than A is travelled by B.
In one B travels 4m.
So in 5 seconds, 5*4=20m.
B travels 20m more than A.
That is A win by 20m.
(4)

Ash said:   9 years ago
Speed is directly proportional to distance.

3/4 = (500-140)/(500-x).

3/4 = 360/(500-x).

Hence x = 20.
(1)

Damini.arora said:   9 years ago
Here, because A has a start of 140, he has already covered 140 m when B starts. So when A covers rest of 360, B covers 480.

Hence B loses race by 20 m.

Newstein Faraday . said:   10 years ago
A has to travel 360 meters therefore Time =distance/ speed. So 360/3 = 120 seconds.

The same 120 seconds b has to travel so distance = speed x time = 4 x 120 = 480.

The remaining distance that b has to travel is 500-480 = 20.
(1)

Srinu said:   1 decade ago
Time = dis\speed.

T = 360\3 = 120sec.
Now dis = sxT = 4x120 = 480m.

So 500-480 = 20m.
This is the answer.

Rajesh said:   1 decade ago
Can be solved by simple calculation.

A covers 360m (ie) 500-140.

Ratio of speeds of A:B = 3:4.

Let us consider A covers 3m/sec & B covers 4m/sec.

Time taken by A to cover 360m=(360/3)=120seconds.

So,Distance covered by B in 120s =120*4=480m.

Therefore,A wins by 20 metres which is (500-480).

Manojit said:   1 decade ago
While A covers 3 m, B covers 4 m.
While A covers 1m, B covers 4/3 m.
While A covers 360 m, B covers (4/3* 360)m =480 m.
Here time is same in case of speed.we count different distance in same time.


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