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 11 of 12.
Tarannum said:
1 decade ago
Thanks siddharth
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
Kavitha said:
1 decade ago
Thanks sid.
Hussain said:
1 decade ago
Thanks to Sidd and Abhishe.
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)
Sali said:
1 decade ago
How 1hr 40min 48sec=1 51/75
Prachi said:
1 decade ago
Thanks sid...
Mitali said:
1 decade ago
Thanks Siddharth.
Siddharth said:
1 decade 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)
Shwetha said:
1 decade ago
1 hr 40min 48sec means 1hr 40min 48/60*60=1hr 40min 1/75 means converting sec in to min then min in to hrs.
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