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 2 of 10.
Anuj said:
3 years ago
10 kmph (2 pm) = t h ----> eq(1)
x kmph (1 pm) = (t-1)h ----> eq(2)
15 kmph (2 pm) = (t-2)h ----> eq(3)
Since, distance is the same for all cases we can equate these equations to get the answer.
x kmph (1 pm) = (t-1)h ----> eq(2)
15 kmph (2 pm) = (t-2)h ----> eq(3)
Since, distance is the same for all cases we can equate these equations to get the answer.
(6)
Rabin said:
1 year ago
Thanks for the explanation @Farzana.
(4)
Havoc said:
5 years ago
We can also use average speed formula.
Because 12 am to 2 pm time 2 hr.
Thus 12 am to 1 am 1 hr.
So, we can find use avg speed also,
The mid point time of 12 am and 2 pm is 1 pm.
Because 12 am to 2 pm time 2 hr.
Thus 12 am to 1 am 1 hr.
So, we can find use avg speed also,
The mid point time of 12 am and 2 pm is 1 pm.
(3)
Ranjith said:
5 years ago
Solution:
2xy/x+y >this is a formula.
2(10)(15)/10 + 15.
300/25 = 12kmph.
2xy/x+y >this is a formula.
2(10)(15)/10 + 15.
300/25 = 12kmph.
(3)
Pavan sai said:
7 years ago
It's very easy by using relative speed concept there are two things up there.
So, now by using the formula 2xy/x+y.
where x=10 and y=15,
=> 2*10*15/10+15,
=>300/25,
=>12,
So the answer is 12kmph.
So, now by using the formula 2xy/x+y.
where x=10 and y=15,
=> 2*10*15/10+15,
=>300/25,
=>12,
So the answer is 12kmph.
(2)
Aamir said:
1 decade ago
We can also solve through avearge speed its easy .x=10,y=15
2xy/x+y
2*10*15/10+15=
300/25=12
2xy/x+y
2*10*15/10+15=
300/25=12
(2)
Suma said:
9 years ago
If two distance is equal, here two distance is equal.
Then speed = 2s1s2/s1 + s2.
2 * 10 * 15/(10 + 15) = 12.
Then speed = 2s1s2/s1 + s2.
2 * 10 * 15/(10 + 15) = 12.
(1)
Muhammad ali said:
6 years ago
Why don't you just find the mean value?
With 10kmph reach at 2 p.m.
Witn 15kmph reach at 12noon.
Find mean of both for 1p.m required time.
So, 10+15 = 25/2 = 12.5kmph should be the correct answer.
With 10kmph reach at 2 p.m.
Witn 15kmph reach at 12noon.
Find mean of both for 1p.m required time.
So, 10+15 = 25/2 = 12.5kmph should be the correct answer.
(1)
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)
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)
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