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:
95 comments Page 2 of 10.
Anuj said:
4 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:
2 years ago
Thanks for the explanation @Farzana.
(5)
Ranjith said:
6 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)
Havoc said:
6 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)
Aamir said:
2 decades 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)
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)
Muhammad ali said:
7 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:
6 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)
Suma said:
10 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)
Harsha Vardhan said:
4 weeks ago
For this type of qs, we simply found the distance by using the formula,
(s1 x s2)/s2-s1 x time difference.
Here s1 = 10.
s2 = 15.
Time difference = 2 hours(12 pm -2pm)
By applying the formula, we get 10 x 15/15 - 10 x 2.
150/5 x 2,
30 x 2 = 60.
(s1 x s2)/s2-s1 x time difference.
Here s1 = 10.
s2 = 15.
Time difference = 2 hours(12 pm -2pm)
By applying the formula, we get 10 x 15/15 - 10 x 2.
150/5 x 2,
30 x 2 = 60.
(1)
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