Aptitude - Time and Distance - Discussion
Discussion Forum : Time and Distance - General Questions (Q.No. 15)
15.
A man covered a certain distance at some speed. Had he moved 3 kmph faster, he would have taken 40 minutes less. If he had moved 2 kmph slower, he would have taken 40 minutes more. The distance (in km) is:
Answer: Option
Explanation:
Let distance = x km and usual rate = y kmph.
| Then, | x | - | x | = | 40 |  2y(y + 3) = 9x ....(i) |
| y | y + 3 | 60 |
| And, | x | - | x | = | 40 | y(y - 2) = 3x ....(ii) |
| y -2 | y | 60 |
On dividing (i) by (ii), we get: x = 40.
Discussion:
118 comments Page 11 of 12.
Shiva said:
8 years ago
Why they took 60 there, please can anyone give a brief explanation regarding those equations x/y - (x/(y+3)) = 40/60? And the second equation as well.
Jyo said:
8 years ago
Formulae:speed=distance/time.
Case 1:
3=d/t-40
3t-120=d ---> eq(1)
Case 2:
2=d/t+40
2t+80=d ---> eq(2).
After solving eq(1) and eq(2), we get.
t=49.
Case 1:
3=d/t-40
3t-120=d ---> eq(1)
Case 2:
2=d/t+40
2t+80=d ---> eq(2).
After solving eq(1) and eq(2), we get.
t=49.
Hariom saini said:
7 years ago
You can also solve it like;
If T1=T2=40 than
V=2V1V2/V1-V2
=2*3*2/3-2
=12.
Than X=V*T1(1+V/V1)
= 12*40/60(1+12/3)
= 8*5
=40KM.
T1=40/60hr V=speed V1=12km/hr.
If T1=T2=40 than
V=2V1V2/V1-V2
=2*3*2/3-2
=12.
Than X=V*T1(1+V/V1)
= 12*40/60(1+12/3)
= 8*5
=40KM.
T1=40/60hr V=speed V1=12km/hr.
Hemanth said:
7 years ago
@Amit.
Please, can you explain how to solve those 3 equations in a easy or some possible method? Please tell me.
Please, can you explain how to solve those 3 equations in a easy or some possible method? Please tell me.
Vivek said:
7 years ago
This sum is not understand clearly please explain clearly.
Jaideep said:
7 years ago
Ans-3/10+3/20+3/30+3/60=6/10 Hrs,
therefore 12/6/10=20 km/ph.
therefore 12/6/10=20 km/ph.
Ruku said:
7 years ago
The distance is simply.
As if he is speed 3kmph then it takes 40 less,
And if his speed 2kmph then it takes 40 more,
(3 * 40)-(2 * 40)=120-80.
= 40km.
As if he is speed 3kmph then it takes 40 less,
And if his speed 2kmph then it takes 40 more,
(3 * 40)-(2 * 40)=120-80.
= 40km.
Damu said:
7 years ago
Just from simple trick, it is.
3 * 40 - 2 * 40 = 40.
3 * 40 - 2 * 40 = 40.
Varun said:
7 years ago
d=s*t,
t=40 mins.
s=3 km/hr-2km/hr =1 km/h,
d=1*40=40km/hr.
t=40 mins.
s=3 km/hr-2km/hr =1 km/h,
d=1*40=40km/hr.
Shreeshail karajol said:
7 years ago
How come 40/60? Please explain.
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