Aptitude - Time and Distance - Discussion
Discussion Forum : Time and Distance - General Questions (Q.No. 12)
12.
Robert is travelling on his cycle and has calculated to reach point A at 2 P.M. if he travels at 10 kmph, he will reach there at 12 noon if he travels at 15 kmph. At what speed must he travel to reach A at 1 P.M.?
Answer: Option
Explanation:
Let the distance travelled by x km.
| Then, | x | - | x | = 2 |
| 10 | 15 |
3x - 2x = 60
x = 60 km.
| Time taken to travel 60 km at 10 km/hr = |  |
60 |  hrs |
= 6 hrs. |
| 10 |
So, Robert started 6 hours before 2 P.M. i.e., at 8 A.M.
 Required speed = |
|
60 | kmph. |
= 12 kmph. |
| 5 |
Discussion:
93 comments Page 5 of 10.
Vyshu said:
1 decade ago
Why we are subtracting here i.e., x/10-x/15=2;.
And in the next problem why we are adding. Can anyone explain when should add and when should subtract.
And in the next problem why we are adding. Can anyone explain when should add and when should subtract.
(1)
Shilpa said:
1 decade ago
Why we are subtracting here i.e., x/10-x/15=2;?
And in the next problem why we are adding. Can anyone explain when should add and when should subtract.
And in the next problem why we are adding. Can anyone explain when should add and when should subtract.
Vinitha said:
5 years ago
As the time is in AP.
Speeds are in HP.
15kmph ---> 12 pm
X kmph ---> 1pm
10kmph ---> 2 pm.
HP = 2 * 15 * 10/15 + 10,
=300/25,
=12kmph.
Speeds are in HP.
15kmph ---> 12 pm
X kmph ---> 1pm
10kmph ---> 2 pm.
HP = 2 * 15 * 10/15 + 10,
=300/25,
=12kmph.
(1)
Jethalal said:
6 years ago
@Vani.
If you want to reach at 1 P. M. Then from 8 o'clock to 1 the time comes out to be 5 hrs so we have taken 5hrs and from that we got speed.
If you want to reach at 1 P. M. Then from 8 o'clock to 1 the time comes out to be 5 hrs so we have taken 5hrs and from that we got speed.
Vishu said:
1 decade ago
x/10-x/15=2
=>3x-2x=60
I didn't get the proper method.
How it comes anyone could tell me briefly it will be helpful for me.
=>3x-2x=60
I didn't get the proper method.
How it comes anyone could tell me briefly it will be helpful for me.
Prathamesh Pendal said:
5 years ago
1pm is in between 12 and 2 pm.
So, if we find average speed we can also get the answer.
Avg speed = (2*15*10)/(10+15) = 12.
So, if we find average speed we can also get the answer.
Avg speed = (2*15*10)/(10+15) = 12.
(57)
Aarti said:
1 decade ago
Nice method @Rahul Mathur.
The only thing is you have calculated value of t=10 wrongly.
It comes out to be 6. Check out.
The only thing is you have calculated value of t=10 wrongly.
It comes out to be 6. Check out.
Ashish said:
2 decades ago
Actually 5 comes as:
Robert start travelling at 8 am. Now difference between 8 am to 1 pm is 5 hrs.
So that 60/5.
Robert start travelling at 8 am. Now difference between 8 am to 1 pm is 5 hrs.
So that 60/5.
Sagar said:
8 years ago
8 am to 1 pm= 5 hours.
Distance:-60 and time:-5.
Therefore: 60/5 is taken at last step.
i.e: speed:-distance/ time.
Distance:-60 and time:-5.
Therefore: 60/5 is taken at last step.
i.e: speed:-distance/ time.
Rinn sailo said:
8 years ago
Just take average speed.
Required speed.
= 2xy/(x+y),
=(2 x 10 x 15)/(10+15),
= 300/25.
= 12Km/hr.
That's it.
Required speed.
= 2xy/(x+y),
=(2 x 10 x 15)/(10+15),
= 300/25.
= 12Km/hr.
That's it.
Post your comments here:
Quick links
Quantitative Aptitude
Verbal (English)
Reasoning
Programming
Interview
Placement Papers