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 4 of 12.
Prachi said:
1 decade ago
Thanks sid...
Sali said:
1 decade ago
How 1hr 40min 48sec=1 51/75
ABHISHEK said:
1 decade ago
1hr 40min 48sec = 1hr +(40)min +(48/60)min
= 1hr +(40)min +(4/5)min [as,(4/5)=(8/10)=0.8]
= 1hr +(40.8)min
= 1hr +(40.8/60)hr [as,(40.8/60)=(68/100)]
= 1hr +(0.68)hr
= 1.68hr
According to question,
(5/7)x * 1.68 = 42 (where, x- actual speed)
Solving this we get, x = 35km/hr(actual speed)
= 1hr +(40)min +(4/5)min [as,(4/5)=(8/10)=0.8]
= 1hr +(40.8)min
= 1hr +(40.8/60)hr [as,(40.8/60)=(68/100)]
= 1hr +(0.68)hr
= 1.68hr
According to question,
(5/7)x * 1.68 = 42 (where, x- actual speed)
Solving this we get, x = 35km/hr(actual speed)
Hussain said:
1 decade ago
Thanks to Sidd and Abhishe.
Kavitha said:
1 decade ago
Thanks sid.
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
Tarannum said:
1 decade ago
Thanks siddharth
Bharath kumar said:
1 decade ago
Thanks sid.
Zabi said:
1 decade ago
How is 40 4/5 is converted to 51/75?
Nikita said:
1 decade ago
Let first consider 48sec
So, 48/60=4/5 min
then
40+4/5=204/5;
Convert this into hour
i.e (204/5)/60=51/75
Total
1+(51/75)=126/75
So, 48/60=4/5 min
then
40+4/5=204/5;
Convert this into hour
i.e (204/5)/60=51/75
Total
1+(51/75)=126/75
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