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:
141 comments Page 2 of 15.
Ansh Raghav said:
7 months 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.
(21)
Himanshu said:
9 months ago
Let the Distance = 2x.
So, By Formula T = D/S.
The distance covered by each = x.
10 = x/21+x/24,
5040 = 45x,
X = 122.
So Distance =2x,
= 2x122,
=224 Km.
So, By Formula T = D/S.
The distance covered by each = x.
10 = x/21+x/24,
5040 = 45x,
X = 122.
So Distance =2x,
= 2x122,
=224 Km.
(19)
Sathya said:
2 years ago
T = 10hrs.
Distance = x
For first half,
when the distance is x/2, speed is 21km/hr.
For the second half
when the distance is x/2, the speed is 24km/hr.
then ,time=distance/speed.
10 = x/2/21+x/2/24;
10 = x/42+x/48,
10 = (48x+42x)/2016,
20160 = 90x,
x = 224km.
Distance = x
For first half,
when the distance is x/2, speed is 21km/hr.
For the second half
when the distance is x/2, the speed is 24km/hr.
then ,time=distance/speed.
10 = x/2/21+x/2/24;
10 = x/42+x/48,
10 = (48x+42x)/2016,
20160 = 90x,
x = 224km.
(18)
Ravinder Choudhary said:
2 years ago
X/21 + X/24 = 10,
15X/168 = 10,
X = 112,
2X = 224.
15X/168 = 10,
X = 112,
2X = 224.
(18)
Bhavin said:
3 years ago
x/21 + x/24 = 20.
24x + 21x = 20* 21 *24,
45x = 10,080,
x =10,080/45.
Ans x = 224.
24x + 21x = 20* 21 *24,
45x = 10,080,
x =10,080/45.
Ans x = 224.
(8)
Shivasagar said:
2 years ago
= 2 x 21 * 24/21 + 24 * 10.
= 224.
= 224.
(8)
Aleena said:
3 years ago
Let the time taken for the complete first half = x.
Then the time taken for complete second half will be = 10 - x.
Distance = speed * time.
So,
21x = 24(10-x)
21x = 240-24x
21x + 24x=240
45x = 240
x = 240/45
ie 16/3.
Give the value of x to the first equations.
21x=21 * 16/3.
We get 112.
24(10-x) = 24*(10-16/3).
We get 112.
Just add them both to get the total distance.
ie 224.
Then the time taken for complete second half will be = 10 - x.
Distance = speed * time.
So,
21x = 24(10-x)
21x = 240-24x
21x + 24x=240
45x = 240
x = 240/45
ie 16/3.
Give the value of x to the first equations.
21x=21 * 16/3.
We get 112.
24(10-x) = 24*(10-16/3).
We get 112.
Just add them both to get the total distance.
ie 224.
(7)
Shubham said:
4 years ago
@Naveen.
LCM of 21 and 24 is 168,
168/21 = 7,
168/24 = 8.
But the simple way to solve this question is;
Avrg speed = 2xy/x+y,
2 * 21 * 24/ 21+24,
1008/45 = 22.4.
Distance = speed * time,
= 22.4 *10 =224 km/h.
LCM of 21 and 24 is 168,
168/21 = 7,
168/24 = 8.
But the simple way to solve this question is;
Avrg speed = 2xy/x+y,
2 * 21 * 24/ 21+24,
1008/45 = 22.4.
Distance = speed * time,
= 22.4 *10 =224 km/h.
(6)
Joy said:
2 years ago
I am not understanding this. Please help me to get this.
(6)
Nithin said:
6 months ago
The right answer is 234 km.
(3)
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