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 1 of 10.
Nishit Patel said:
8 months ago
The question is what's the average speed of Robert.
Avg Speed = 2xy/x+y.
= 2 × 10 × 15/10 + 15.
= 300/25.
= 12 km/h.
Avg Speed = 2xy/x+y.
= 2 × 10 × 15/10 + 15.
= 300/25.
= 12 km/h.
(48)
Rabin said:
9 months ago
Thanks for the explanation @Farzana.
(3)
Aasa sri said:
10 months ago
x/10 - x/15 = 2
1/5(x/2-x/3) = 2
3x-2x/6 = 2 * 5
x/6 = 10
x = 60.
60kmph at 10kmph is 60/10 = 6.
So, 12 noon time is 4 and 2 pm time is 6.
Then 1 pm time is b/w them so 5.
The speed is 60/5 = 12kmph.
1/5(x/2-x/3) = 2
3x-2x/6 = 2 * 5
x/6 = 10
x = 60.
60kmph at 10kmph is 60/10 = 6.
So, 12 noon time is 4 and 2 pm time is 6.
Then 1 pm time is b/w them so 5.
The speed is 60/5 = 12kmph.
(6)
Vivek said:
1 year ago
Case1: speed = 10kmph.
Ce2: speed = 15kmph.
Given d/10-d/15 = 2,
d=60,
case1 time=60/10, time=6,
case2 time=60/15, time=4,
so, for 12noom time is 4, and for 2 pm is 6
And 1 pm is between them so it will be 5.
And 60/5=12.
Ce2: speed = 15kmph.
Given d/10-d/15 = 2,
d=60,
case1 time=60/10, time=6,
case2 time=60/15, time=4,
so, for 12noom time is 4, and for 2 pm is 6
And 1 pm is between them so it will be 5.
And 60/5=12.
(27)
Anushree Kulkarni said:
3 years ago
@Farzana.
Best and neat explanation, Thank you.
Best and neat explanation, Thank you.
(7)
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.
(5)
Vicky said:
4 years ago
How 3 came? Please explain.
(7)
Akash said:
4 years ago
@All.
Use formula like (2 (a.b) /a+b) a is speed 10kmph and b is 15kmph.
Hope you get it.
Use formula like (2 (a.b) /a+b) a is speed 10kmph and b is 15kmph.
Hope you get it.
(30)
Prathamesh Pendal said:
4 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.
(56)
Havoc said:
4 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)
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