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 4 of 9.
Sara said:
1 decade ago
Hi @Manisha.
8 is from question see (takes 20 minutes more) than 8 hrs.
So 2 train take 8 hrs 20 minutes.
8 in hour 20 in minutes so convert 20 to hour 20/60.
8(20/60) got it?
8 is from question see (takes 20 minutes more) than 8 hrs.
So 2 train take 8 hrs 20 minutes.
8 in hour 20 in minutes so convert 20 to hour 20/60.
8(20/60) got it?
Malathi p said:
1 decade ago
Hi, from where that 25/3 came? Please clarify my doubt sir.
Malathi said:
1 decade ago
Hai sir where we get 1/15 and 1/24?
Siri said:
10 years ago
I can't understand to 1/x +4/y =1/15 and 1/x +2/y =1st/24 why they take addition in this step?
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.
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.
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.
L.dhanaraj said:
10 years ago
Hi any one tell me short cut?
Narendra said:
10 years ago
There is short cut method equation 1/equation 2.
Nishanth said:
9 years ago
@Satish. Why you have multiply 25/3*200 please explain?
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