Aptitude - Time and Distance - Discussion
Discussion Forum : Time and Distance - General Questions (Q.No. 13)
13.
It takes eight hours for a 600 km journey, if 120 km is done by train and the rest by car. It takes 20 minutes more, if 200 km is done by train and the rest by car. The ratio of the speed of the train to that of the cars is:
Answer: Option
Explanation:
Let the speed of the train be x km/hr and that of the car be y km/hr.
| Then, | 120 | + | 480 | = 8  |
1 | + | 4 | = | 1 | ....(i) |
| x | y | x | y | 15 |
| And, | 200 | + | 400 | = | 25 | |
1 | + | 2 | = | 1 | ....(ii) |
| x | y | 3 | x | y | 24 |
Solving (i) and (ii), we get: x = 60 and y = 80.
Ratio of speeds = 60 : 80 = 3 : 4.
Discussion:
84 comments Page 5 of 9.
Sathish said:
9 years ago
How 120/x + 480/y = 8?
Vikash said:
9 years ago
Change 20 min in an hour then add 8 because take more time we get 25/3.
Abi said:
9 years ago
200/x + 400/y = 25/3.
200 (1/x + 2/y) = 25/3.
1/x + 2/y = 25/3 * 200 (multiply 3 * 200).
1/x + 2/y = 25/600.
1/x + 2/y = 1/24.
By solving this, we get 3 : 4.
200 (1/x + 2/y) = 25/3.
1/x + 2/y = 25/3 * 200 (multiply 3 * 200).
1/x + 2/y = 25/600.
1/x + 2/y = 1/24.
By solving this, we get 3 : 4.
(1)
Deep said:
9 years ago
Can anyone explain it properly how we got 1/24?
Nishanth said:
9 years ago
@Satish. Why you have multiply 25/3*200 please explain?
Narendra said:
10 years ago
There is short cut method equation 1/equation 2.
L.dhanaraj said:
10 years ago
Hi any one tell me short cut?
Rocky said:
10 years ago
8+20/60 = 25/3.
1 hr = 60 min.
1 min = 1/60 hr.
1 hr = 60 min.
1 min = 1/60 hr.
Sunil Kumar said:
10 years ago
@Siri.
Since we have to find the speeds of train and car, we need to solve for x and y. So we need addition here.
Since we have to find the speeds of train and car, we need to solve for x and y. So we need addition here.
Ashish Kapil said:
10 years ago
Is it right or wrong? Please tell me.
200/x+400/y-120/x-480/y = 1/3 or 20 minute.
200/x+400/y-120/x-480/y = 1/3 or 20 minute.
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