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:
117 comments Page 7 of 12.
Vivek said:
2 years ago
Time = 1 + 40/60 + 48/60*60 = 1.68hr
Speed=x,
Given speed 5x/7,
5x/7 = 42/1.68.
x = 35 km/hr.
Speed=x,
Given speed 5x/7,
5x/7 = 42/1.68.
x = 35 km/hr.
(34)
Maddy nikam said:
1 decade ago
1hr 40m = 100 m.
42km/100m = 420 mtr/min.
60min*420 mtr = 25.20kmph.
2520*(7/5) = 35 kmph.
42km/100m = 420 mtr/min.
60min*420 mtr = 25.20kmph.
2520*(7/5) = 35 kmph.
Suraj N Raikar said:
2 years ago
Let 42kmph is the average speed,
And travelling at 5/7 of average speed.
7/5 x 42 = 35kmph.
And travelling at 5/7 of average speed.
7/5 x 42 = 35kmph.
(68)
Avi said:
4 years ago
Isn't Time = Distance/Speed why did they multiply?
Also explain the step : 5/7x*75/126.
Also explain the step : 5/7x*75/126.
(1)
Girishankar said:
9 years ago
Thank you so much for everyone, who are all posted the method of hour conversion. :).
Siba Prasad Sahoo said:
8 years ago
First modify all in hour.
So,
1hour+ 40/60hour+48/3600hour,
1+2/3+1/75=126/75 hour.
So,
1hour+ 40/60hour+48/3600hour,
1+2/3+1/75=126/75 hour.
Akshay said:
2 years ago
Short trick;
= 5/7×42;
= 30.
= 2xy/x+y
= 2 * 42 * 30/42 + 30
= 2520/72.
= 35km/hrs.
= 5/7×42;
= 30.
= 2xy/x+y
= 2 * 42 * 30/42 + 30
= 2520/72.
= 35km/hrs.
(107)
Raju said:
1 decade ago
42/1.68 is 25kmph but there is 5/7 of speed so 5/7x=25 ok solve it
x=25*7/5=35kmph
x=25*7/5=35kmph
Poojith said:
4 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)
Vineeth said:
9 years ago
Easiest Method:.
Speed = dis/time.
Let speed = x.
5/7(x) = 42/(126/75) = 35.
Speed = dis/time.
Let speed = x.
5/7(x) = 42/(126/75) = 35.
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