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 1 of 12.
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.
(106)
Sree ezhil said:
4 years ago
Simple method:
S1: covert seconds to minutes
48/60 =0.8min ; 40min+0.8min =40.8min.
S2: convert min to sec.
40.8/60 =0.68 ; 0.68hr+1hr= 1.68hr
S3: for avg speed
5/7 x= 42/1.68,
5/7x = 25,
x = 25 * 7/5,
x = 35.
Hope you guys understand easily.
S1: covert seconds to minutes
48/60 =0.8min ; 40min+0.8min =40.8min.
S2: convert min to sec.
40.8/60 =0.68 ; 0.68hr+1hr= 1.68hr
S3: for avg speed
5/7 x= 42/1.68,
5/7x = 25,
x = 25 * 7/5,
x = 35.
Hope you guys understand easily.
(84)
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)
Sherief said:
2 years ago
Simplest form;
S = D ÷ T formula;
S = 5s ÷ 7.
42km~convert in meter so, 4200.
1hr+40min+48sec.
= (60min × 60sec) + (40min × 60sec) + 48sec,
= 6048.
S = D÷T.
5s ÷ 7 = 4200 ÷ 6048.
= 4200×7 ÷ 6048 ÷ 5
= 8400 ÷ 864,
= 350 ÷ 36.
To change in m/s to km/hr so;
= (350÷36)×18÷5.
= 35km/hr answer.
S = D ÷ T formula;
S = 5s ÷ 7.
42km~convert in meter so, 4200.
1hr+40min+48sec.
= (60min × 60sec) + (40min × 60sec) + 48sec,
= 6048.
S = D÷T.
5s ÷ 7 = 4200 ÷ 6048.
= 4200×7 ÷ 6048 ÷ 5
= 8400 ÷ 864,
= 350 ÷ 36.
To change in m/s to km/hr so;
= (350÷36)×18÷5.
= 35km/hr answer.
(48)
Dhivya said:
2 years ago
T = 1hr40min48sec.
= 1hr40(48/60)min,
= 1hr40(4/5)min,
= 1hr(204/5*60)min,
= 1(51/75)hr,
= 126/75 hr,
Then, Actual speed = (5/7x)*(126/75) = 42.
X = (42*7*75/15*126) = 35km/hr.
= 1hr40(48/60)min,
= 1hr40(4/5)min,
= 1hr(204/5*60)min,
= 1(51/75)hr,
= 126/75 hr,
Then, Actual speed = (5/7x)*(126/75) = 42.
X = (42*7*75/15*126) = 35km/hr.
(34)
Mohd younis said:
3 years ago
1hrs 40 min 48sec.
1 + 40/60 + 48/60 * 60 = 42/25 = 1.68 hours.
1 + 40/60 + 48/60 * 60 = 42/25 = 1.68 hours.
(32)
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.
(32)
KUMARI SUPRITA said:
3 years ago
1hr + 40min + 48sec = 1 + (40/60) + (48/60*60).
= 1 + 2/3 + 1/75 = 126/75.
= 1 + 2/3 + 1/75 = 126/75.
(28)
Jenny said:
2 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.
(15)
Tenzin said:
1 year ago
@Dhivya.
How you get 204? Please explain.
How you get 204? Please explain.
(12)
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