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 7 of 12.
Thanuj said:
8 years ago
3 * 40 = 120,
2 * 40 = 80,
120-80 = 40.
Does this process will come? Please tell me.
2 * 40 = 80,
120-80 = 40.
Does this process will come? Please tell me.
Amit said:
8 years ago
Hi,
3*40 =120
2*40 = 80
120-80 = 40.
In this one quantity is in hr and second one is in minutes how you cancel the different units.
km/hr*min not relevant.
3*40 =120
2*40 = 80
120-80 = 40.
In this one quantity is in hr and second one is in minutes how you cancel the different units.
km/hr*min not relevant.
Akash Kishor said:
8 years ago
LET'S SOLVE IN VERY EASY MANNER.
Easiest formula :- DISTANCE = (s1*s2)/(speed difference) * time difference
So, now
D= {s*(s+3)/3} * 40/60 = {s*(s-2)/2} * 40/60.
=> (s+3)/3 = (s-2)/2 [ s and 40/60 will cancel out each other at both side],
=> 2s+6 = 3s-6,
=> s = 12 km/hr.
And now,
D= (12*15)/3 * 40/60 = 40 km Ans. [ according to formula].
Easiest formula :- DISTANCE = (s1*s2)/(speed difference) * time difference
So, now
D= {s*(s+3)/3} * 40/60 = {s*(s-2)/2} * 40/60.
=> (s+3)/3 = (s-2)/2 [ s and 40/60 will cancel out each other at both side],
=> 2s+6 = 3s-6,
=> s = 12 km/hr.
And now,
D= (12*15)/3 * 40/60 = 40 km Ans. [ according to formula].
Neeraj said:
8 years ago
3/x+3/2/x-2= 40/40.
On solving we get x = 12.
On solving we get x = 12.
Manik said:
8 years ago
Please, can anyone solve this equation in details?
On dividing (i) by (ii), we get: x = 40.
On dividing (i) by (ii), we get: x = 40.
Uroosa said:
8 years ago
@Sivaram.
How can you multiply km/hr with minutes without changing it to hours?
How can you multiply km/hr with minutes without changing it to hours?
Sonu kumar said:
8 years ago
@Akash.
I can't understand why have you divided by e3 and 2 on both side of equations. Can you explain please?
I can't understand why have you divided by e3 and 2 on both side of equations. Can you explain please?
Puneet negi said:
8 years ago
How can we get the answer in km when the time is given in minutes? @Shivraman.
Puneet negi said:
8 years ago
S(s+3)*40/60 = s(s-2)*40/60
----------------------. ------------------
3. 2
S=12 putting in any of side l.h.s or r.h. s we get required answer 40.
----------------------. ------------------
3. 2
S=12 putting in any of side l.h.s or r.h. s we get required answer 40.
Pooja Gupta said:
8 years ago
Man goes to his office at a certain speed. If he travels at a speed 4kmph more than his usual speed then he will reach his office early by 12 minutes. If he travels at a speed 8 kmph less than his usual speed he will be late by 36 minutes. Find his original speed.
How would we solve it?
How would we solve it?
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