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by rijul007 » Mon Nov 07, 2011 7:59 pm
1 min = 6 degrees

6 degrees moved by minutes hand => 6/12 degree moved by hours hand
Lets say minute and hour hands form a rigt angle x mins after 2 o'clock

6x - [6*10 + x/2] = 90
11x/2 -60 = 90
11x/2 = 150
x = 150*2/11 =27.27

The two hands will be perpendicular 27.3 mins after 2 o'clock
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by user123321 » Mon Nov 07, 2011 8:25 pm
silverflamein wrote:At what time after 2 o'clock, the hour hand and the minute hand of a clock form a right angle ???
hours hand makes 30 degrees for each hour on a clock = 360/12
minutes hand makes 6 degrees for each minute on a clock = 360/60

lets say after x minutes after 2 clock there was a 90 degrees difference between two hands.
then
6x - (2+x/60)30 = 90
11x/2 = 150
x = 300/11 = 27 3/11
Just started my preparation :D
Want to do it right the first time.
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by GmatKiss » Mon Nov 07, 2011 10:58 pm
silverflamein wrote:At what time after 2 o'clock, the hour hand and the minute hand of a clock form a right angle ???
This is no way a GMAT Q. also always provide choices for the Q
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by saketk » Tue Nov 08, 2011 6:12 am
I agree with GMATKISS on this part. This is surely not a GMAT question not just because the options are not posted but also because this question is incomplete.

Hours and minute hand make right angle many times after 2'o clock.
The question should mention something like - rightangle for the first time, second time or the Nth time.

To original poster - please cite the source of this question.
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by silverflamein » Tue Nov 08, 2011 5:47 pm
Hey Saketk & GMATkiss, I'm sorry for not getting the options as the question i posted originally from a prep book of IMS did not have any. And since i could not solve it myself i posted it online for someone to help me. I have just started preparing myself and do not have any coach or guidance except for the material that i bought from IMS. So i keep posting sums that i find difficult to solve myself.
Hope you can understand and bear with me.

Also these questions may not be GMAT questions but i am not the judge so i thank you for helping me
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