Aptitude - Time and Distance - Discussion
Discussion Forum : Time and Distance - General Questions (Q.No. 7)
7.
A man complete a journey in 10 hours. He travels first half of the journey at the rate of 21 km/hr and second half at the rate of 24 km/hr. Find the total journey in km.
Answer: Option
Explanation:
| (1/2)x | + | (1/2)x | = 10 |
| 21 | 24 |
 |
x | + | x | = 20 |
| 21 | 24 |
15x = 168 x 20
| x = |
 |
168 x 20 |  |
= 224 km. |
| 15 |
Discussion:
144 comments Page 1 of 15.
AANI said:
3 years ago
Total journey = 10 hours.
Journey in 2 parts 10/2 = 5
each journey is = 5 hours.
1st journey speed =21 km/hr ;
Total of 1st journey speed = 21 x 5 =105
Total of 2nd journey speed =24 x 5 =120.
Then,
Total 1st and 2nd both journey speed = 105 + 120 = 225 km.
THANKS.
Journey in 2 parts 10/2 = 5
each journey is = 5 hours.
1st journey speed =21 km/hr ;
Total of 1st journey speed = 21 x 5 =105
Total of 2nd journey speed =24 x 5 =120.
Then,
Total 1st and 2nd both journey speed = 105 + 120 = 225 km.
THANKS.
(388)
Akshay said:
3 years ago
Total journey = 10hours.
Journey in 2 parts = 10/2 = 5.
Each journey is = 5hours.
1st journey speed = 21km/hr.
2nd journey speed = 24km/hr.
Total of 1st journey speed = 21 * 5 = 105
Total of 2nd journey speed = 24 * 5 = 120.
So,
Total 1st & 2nd both journey = 105 + 120.
= 225km.
Journey in 2 parts = 10/2 = 5.
Each journey is = 5hours.
1st journey speed = 21km/hr.
2nd journey speed = 24km/hr.
Total of 1st journey speed = 21 * 5 = 105
Total of 2nd journey speed = 24 * 5 = 120.
So,
Total 1st & 2nd both journey = 105 + 120.
= 225km.
(90)
Rakshii said:
4 years ago
First, half of the journey is nothing but 5hr,
So, distance = speed * time.
21*5 = 105.
24*5 = 120.
Total= 225km
So, distance = speed * time.
21*5 = 105.
24*5 = 120.
Total= 225km
(70)
Hardik H Bagaria said:
2 years ago
@All.
For the people who got an answer as 225km, we cannot assume that the time taken to complete half of the journey (distance) is 5hrs, assuming 5hrs for the first trip and 5 for the second is wrong.
Because its not relative to the time, but rather relative to the journey (distance).
For the people who got an answer as 225km, we cannot assume that the time taken to complete half of the journey (distance) is 5hrs, assuming 5hrs for the first trip and 5 for the second is wrong.
Because its not relative to the time, but rather relative to the journey (distance).
(49)
Akshay said:
3 years ago
2xy/x+y.
= 2*21*24/21+24.
= 1008/45
= 224km.
= 2*21*24/21+24.
= 1008/45
= 224km.
(38)
Pradumn said:
2 years ago
By using the formula = 2xy/x + y.
= 2 * 21 * 24/21 + 24.
= 1008/45,
= 22.4,
= 22.4 * 10.
= 224km.
= 2 * 21 * 24/21 + 24.
= 1008/45,
= 22.4,
= 22.4 * 10.
= 224km.
(37)
Gowthaman said:
1 year ago
Let's take a formula = 2XY/X + Y.
Here, X=21 and Y= 24.
So, the formula is = 2 * 21 * 24/21 + 24,
= 1008/45.
Here, your Answer = 22.4 * 10 = 224.
Here, X=21 and Y= 24.
So, the formula is = 2 * 21 * 24/21 + 24,
= 1008/45.
Here, your Answer = 22.4 * 10 = 224.
(32)
Sivaprakash said:
3 years ago
It may easily be by using averages for 10 hrs- (5*21)+(24*5) = 22.5.
And D = S*T.
22.5 * 10 = 225km
And D = S*T.
22.5 * 10 = 225km
(30)
VISHNU said:
6 months ago
Time = 10hr.
Speed = 21 and 24, 21 + 24 = 45.
Distance = speed * time.
Distance = 10*45 = 450.
The journey is 2 parts.
450/2 = 225 ~224.
Speed = 21 and 24, 21 + 24 = 45.
Distance = speed * time.
Distance = 10*45 = 450.
The journey is 2 parts.
450/2 = 225 ~224.
(27)
Ansh Raghav said:
1 year ago
@ALL.
According to the given question;
x/21 + x/24 =10
15x/168 = 10.
By cross multiplication;
168 × 10 = 15x.
1680 = 15x.
122 = x.
2x = 224.
According to the given question;
x/21 + x/24 =10
15x/168 = 10.
By cross multiplication;
168 × 10 = 15x.
1680 = 15x.
122 = x.
2x = 224.
(26)
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