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 6 of 12.
Sandeep Ippakayala said:
8 years ago
5/7u=42/1+2/3+1/75,
5/7u=42/126/75,
5/7u=42*75/126,
5/7u=3150/126,
5*126u=3150 * 7,
630u=22050,
u = 35KM.
Time in Hours:
1*75/75+2*25/3*25+1/75.
75+50+1/75.
126/75.
1hr=60min.
1/60hr=1min.
1min=60sec.
1/60min=1sec.
5/7u=42/126/75,
5/7u=42*75/126,
5/7u=3150/126,
5*126u=3150 * 7,
630u=22050,
u = 35KM.
Time in Hours:
1*75/75+2*25/3*25+1/75.
75+50+1/75.
126/75.
1hr=60min.
1/60hr=1min.
1min=60sec.
1/60min=1sec.
Suraj said:
9 years ago
Sir, how to change any fraction in time?
Like
7/5 = _ hour, _min?
Like
7/5 = _ hour, _min?
Avi goyal said:
9 years ago
Time = 1 hr 40 min 48 sec.
= 1hr + 40/60hr + 48/3600 hr = 1 + 2/3 + 1/75 = 126/75 hr.
Distance = 42 km.
Speed = distance/time = 42/(126/75) = 42 * 75/126.
5/7 of the actual speed = 42 * 75/126.
Actual speed = 42 * 75/126 * 7/5.
= 42 * 15/18.
= 7 * 15/3.
= 7 * 5 = 35 km/hr.
= 1hr + 40/60hr + 48/3600 hr = 1 + 2/3 + 1/75 = 126/75 hr.
Distance = 42 km.
Speed = distance/time = 42/(126/75) = 42 * 75/126.
5/7 of the actual speed = 42 * 75/126.
Actual speed = 42 * 75/126 * 7/5.
= 42 * 15/18.
= 7 * 15/3.
= 7 * 5 = 35 km/hr.
Ganesh said:
9 years ago
Actual distance covered by car is 42 km in 1 hr 40 min 48 sec = 100.8 minutes. Now just divide total km by total minutes took = 42/100.8 = 0.416667 km per minute.
Then per hr speed = 0.416667 km per minute * 60 minutes = 25 kmph as the car was running @ 5/7 of it's actual speed.
Then 5 = 25 and 7 = ?
The answer is 25/5 = 5.
5 * 7 = 35 kmph.
Then per hr speed = 0.416667 km per minute * 60 minutes = 25 kmph as the car was running @ 5/7 of it's actual speed.
Then 5 = 25 and 7 = ?
The answer is 25/5 = 5.
5 * 7 = 35 kmph.
Sameen said:
9 years ago
@Abhishek.
Why you have written 4/5 as 8/10?
Why you have written 4/5 as 8/10?
ROhit said:
9 years ago
@ Divya.
1hr = 60min
1min = 60 sec
Then 60min = 60 * 60 sec.
Thus 1 hr = 60 * 60 sec = 3600 sec.
Hope it helps.
1hr = 60min
1min = 60 sec
Then 60min = 60 * 60 sec.
Thus 1 hr = 60 * 60 sec = 3600 sec.
Hope it helps.
Divya said:
9 years ago
Can anyone please say answer that how to convert the hour to min and hour to sec?
Please anyone tell me the answer.
Please anyone tell me the answer.
Chetan said:
9 years ago
Speed * time = distance.
Let assume Actual speed be = x,
Distance = 42,
Time = 1 + (40÷60) + (48÷ 3600) = 1.68,
Hence 5x/7* 1.68 = 42,
5x/7 = 42/1.68,
5x/7 = 25,
5x = 25 * 7,
5x = 175,
X = 175/5,
And X = 35.
Let assume Actual speed be = x,
Distance = 42,
Time = 1 + (40÷60) + (48÷ 3600) = 1.68,
Hence 5x/7* 1.68 = 42,
5x/7 = 42/1.68,
5x/7 = 25,
5x = 25 * 7,
5x = 175,
X = 175/5,
And X = 35.
Yogi said:
9 years ago
Because Actual speed is X and actual speed 5/7 so X. 5/7.
Akshaya said:
9 years ago
Why we multiply by 5/7?
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