Aptitude - Time and Distance - Discussion
Discussion Forum : Time and Distance - General Questions (Q.No. 10)
10.
A car travelling with 
of its actual speed covers 42 km in 1 hr 40 min 48 sec. Find the actual speed of the car.
of its actual speed covers 42 km in 1 hr 40 min 48 sec. Find the actual speed of the car.
Answer: Option
Explanation:
| Time taken = 1 hr 40 min 48 sec = 1 hr 40 | 4 | min = 1 | 51 | hrs = | 126 | hrs. |
| 5 | 75 | 75 |
Let the actual speed be x km/hr.
| Then, | 5 | x x | 126 | = 42 |
| 7 | 75 |
 x = |
 |
42 x 7 x 75 |  |
= 35 km/hr. |
| 5 x 126 |
Discussion:
118 comments Page 2 of 12.
Jenny said:
3 years ago
As the ratio of the car's own speed is given;
5 is the new speed of the car and 7 is the old speed of the car.
As the distance is constant;
The ratio of time is reverse that is 7:5
Thus if 7 = 100.8 (hours into minutes).
1 = 14.4.
5 = 72.
Convert this into an hour, you will get 1.2.
42km distance divided by 1.2 times = 35kmph.
5 is the new speed of the car and 7 is the old speed of the car.
As the distance is constant;
The ratio of time is reverse that is 7:5
Thus if 7 = 100.8 (hours into minutes).
1 = 14.4.
5 = 72.
Convert this into an hour, you will get 1.2.
42km distance divided by 1.2 times = 35kmph.
(16)
Some people said:
4 years ago
How come 126? Please explain.
(11)
Kailash said:
4 years ago
@Nikita,
Please solve and explain the following step.
(204/5)/60 = 51/75.
Like if I do (204/5)/60 = 4.8/60 = 0.08.
Please solve and explain the following step.
(204/5)/60 = 51/75.
Like if I do (204/5)/60 = 4.8/60 = 0.08.
(8)
Vijay said:
4 years ago
Thanks @Siddharth.
(4)
Ranjana said:
4 months ago
Let us assume the average speed is 42m.
and the travelling at 5/7 of the average speed is;
5/7 * 42 = 30.
Formula:
2 * x * y/x + y.
2 * 42 * 30/42 + 30,
2 * 42 * 30/72,
= 35.
and the travelling at 5/7 of the average speed is;
5/7 * 42 = 30.
Formula:
2 * x * y/x + y.
2 * 42 * 30/42 + 30,
2 * 42 * 30/72,
= 35.
(4)
Varshini said:
6 years ago
1hr 40min 40sec = (60x60) + (40x60) + 48.
3600 + 2400 + 48.
6048.
Now converting into the min and then to hr.
6048/60 = 100.8 min.
100.8/60 = 1.68 hr
3600 + 2400 + 48.
6048.
Now converting into the min and then to hr.
6048/60 = 100.8 min.
100.8/60 = 1.68 hr
(2)
Poojith said:
5 years ago
1hr 40min and 48sec == 1.68hours.
5x/7 = 42/1.68,
5x/7 = 25.
5(25)/7 = 35km/hr.
5x/7 = 42/1.68,
5x/7 = 25.
5(25)/7 = 35km/hr.
(2)
Siddharth said:
2 decades ago
1 hr 40min 48sec= 1 + 40/60 + 48/(60*60) hrs
=1+ 2/3 + 4/300
=(300+200+4)/300
=504/300
=126/75
=1+ 2/3 + 4/300
=(300+200+4)/300
=504/300
=126/75
(1)
Sunil pawar said:
8 years ago
@All.
In simple method;
1 hour +40min +48 sec, we have to convert it to an hour.
1+(40/60)+(48/60*60),
1+2/3+(1/75),
=(75+2*25+1)/75,
=126/75.
Now speed * time = distance,
5x/7 * 126/75 = 42 , x is the actual speed of car,
Solving this will give answer x = 35.
In simple method;
1 hour +40min +48 sec, we have to convert it to an hour.
1+(40/60)+(48/60*60),
1+2/3+(1/75),
=(75+2*25+1)/75,
=126/75.
Now speed * time = distance,
5x/7 * 126/75 = 42 , x is the actual speed of car,
Solving this will give answer x = 35.
(1)
Goutham said:
7 years ago
Thanks @Nikita.
(1)
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