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 6 of 10.
Ashish said:
9 years ago
Let the distance be covered 'd'.
Case I: d/t = 10.
Case II: d/t - 2 = 15.
Solving both equations we have t = 10 and d = 60.
To find d/(t-1) = ?
Replacing values of 'd' and 't' will give speed as 12 kmph.
Case I: d/t = 10.
Case II: d/t - 2 = 15.
Solving both equations we have t = 10 and d = 60.
To find d/(t-1) = ?
Replacing values of 'd' and 't' will give speed as 12 kmph.
Neha said:
9 years ago
We can solve this problem by using avg.speed 2xy/x+y.
2 * (10 + 15)/10 + 15,
=12 km/h.
2 * (10 + 15)/10 + 15,
=12 km/h.
Prawesh Pradhan said:
8 years ago
After finding out the distance.
60/10 - 60/x = 1,
5/x = 1,
x = 5.
60/10 - 60/x = 1,
5/x = 1,
x = 5.
Prawesh Pradhan said:
8 years ago
After finding the distance.
60/10-60/x = 1,
6x-60 = x,
5x = 60,
x = 12.
60/10-60/x = 1,
6x-60 = x,
5x = 60,
x = 12.
Aarusi said:
8 years ago
It can be solved easily by applying the average speed formula:
x = 10(given)(speed)
y = 15(given)(speed)
For average speed:
2xy/x + y
2 * 10 * 15/10 + 15 = 12.
x = 10(given)(speed)
y = 15(given)(speed)
For average speed:
2xy/x + y
2 * 10 * 15/10 + 15 = 12.
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.
Ranjith said:
8 years ago
How you are saying starting 8am @Ashish.
Bikash Mahato said:
8 years ago
Let the distance has been travelled be x km.
At the speed of 10 kmph, it will reach 2pm.(equation 1.)
At the speed of 15, it will reach at 12 noon.(equation 2)
And,
At the speed of ?, it will reach at 1pm. (equation 3)
Let's balance the equation.1 and 2,
x/10-x/15=2 hours,
i.e. x=60km.
Now again balance the equation 2 and 3,
60/?-60/15=1 hours,
?=12,
Thus, 12 kmph is the answer.
At the speed of 10 kmph, it will reach 2pm.(equation 1.)
At the speed of 15, it will reach at 12 noon.(equation 2)
And,
At the speed of ?, it will reach at 1pm. (equation 3)
Let's balance the equation.1 and 2,
x/10-x/15=2 hours,
i.e. x=60km.
Now again balance the equation 2 and 3,
60/?-60/15=1 hours,
?=12,
Thus, 12 kmph is the answer.
Tirtha said:
8 years ago
If speed is 10 then he will reach at .2.
If speed 15 then he will reach at 12.
so for 1 pm then we can take avg (10+15)/2=12.5 aprox 12.
Is this correct?
If speed 15 then he will reach at 12.
so for 1 pm then we can take avg (10+15)/2=12.5 aprox 12.
Is this correct?
ELANAGAI said:
8 years ago
How did 60/10 came in the last? Can anyone explain after that?
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