Latest Gate Aptitude Question SOLUTION: 3 wheels make 60,36 and 24 revolutions per min respectively. There is a red spot on the rim of all the 3 wheels. If the red spot was at the bottom most point when they started afte

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(#M40007662) GATE question TIME, SPEED & DISTANCE Keep an EYE

3 wheels make 60,36 and 24 revolutions per min respectively. There is a red spot on the rim of all the 3 wheels. If the red spot was at the bottom most point when they started after how much time would they be at the bottom most point again?

Asked In Gate Chetan Anand (12 years ago)

Unsolved Read Solution (10)

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Sreenivasa Chowdary Nellore  (12 years ago)

They will be together after the L.C.M of the times taken by them to make one revolution

Hence the time taken by 1st wheel to make one revolution = (1/60) min

Second wheel to make one revolution = (1/36) min

Third wheel to make one revolution = (1/24) min

Hence L.C.M of the times taken by them to make one revolution = L.C.M.of(1/60,1/36,1/24) min.

= (1/12) min

i.e. after 5 sec.

This is correct.

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K BASHA  (12 years ago)

Mr PP Singh not 12 sec it is 5 sec

after 5 sec

1 st one will make 5
2 nd one will make 3
3 rd one will make 2

so the ans is 5 sec,

sorry,

not a LCM of 60,36,24 it is LCM of 1/60,1/36,1/24

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Dushyant Kumar  (11 years ago)

5.167 sec.........lcm of 1/60,1/36,1/24

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Pargat Pal Singh  (12 years ago)

After 12 secs or 1/12 mins.

In 1/12 mins, first wheel will make 5 revolutions.
In 1/12 mins, 2nd wheel will make 3 revolutions.
In 1/12 mins, 3rd wheel will make 2 revolutions.

Is this solution Helpfull? Yes (2) | No (3)  

Prerna  (12 years ago)

I think PP Singh is right.

Why to take LCM of 60,36,24 ?

We should take LCM of 1/60 , 1/36, and 1/24 mins.
LCM of 1/60 , 1/36, and 1/24 mins. = 1/12 mins

After 5 secs or 1/12 mins, all 3 will be have red spot at bottom most point.

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Rakesh Kumar Kohli  (12 years ago)

Ans. After 360 minutes i.e 6 hours

Take LCM of 60,36 and 24 which will be 360

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K BASHA  (12 years ago)

do the LCM of 60,36,24 so the answer is 360 min.

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B.Senthil Kumar  (12 years ago)

L.C.M of 60,36,24 is 360
so after 6 hours the red spot in all the three wheel reaches the bottom

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Viru Sihag  (12 years ago)

LCM of (1/60,1/36,1/24) after 5 sec they be at the bottom most point

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kiran  (12 years ago)

ans=360,for common point take LCM of three revolution times

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