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.
Shashank said:
1 decade ago
We can use net speed formula = 2xy/x+y.
Because the distance travelled is same,
So => 2*10*15/(10+15) = 12.
Because the distance travelled is same,
So => 2*10*15/(10+15) = 12.
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)
Saba Azmat said:
1 decade ago
We can also solve dis que by this method,
(2*10*15)/(10+15)=average speed in covering same distance
=12 kmph
(2*10*15)/(10+15)=average speed in covering same distance
=12 kmph
Tbabe said:
1 decade ago
Hi all, it was not specified that he traveled at the same distance?
Am still confused with the solutions.
Am still confused with the solutions.
Raja said:
1 decade ago
Simple one
2pm-12=2 hour
Similarly 15km-10km=5km
5km/2hour=2.5km/h
initial 10+2.5=12.5 nearer to 12
2pm-12=2 hour
Similarly 15km-10km=5km
5km/2hour=2.5km/h
initial 10+2.5=12.5 nearer to 12
Vinaykumar said:
9 years ago
Simple :.
2 speeds calculate average speed 2xy/(x + y).
So,
2 * 10 * 15/(10 + 15).
12km/hr.
2 speeds calculate average speed 2xy/(x + y).
So,
2 * 10 * 15/(10 + 15).
12km/hr.
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)
Akash said:
5 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)
Sree said:
1 decade ago
Average formula can be used when a person travels two equal distances at different speeds.
Pinky said:
1 decade ago
When came to know that on where we have to use this avg formula ?
Please anyone answer.
Please anyone answer.
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