Aptitude - Clock - Discussion

How can answer C is right?

Hey guy do not gossip its right in 1 hr have right angle position came 44 times in 24 hr.

How many times does right angle create in an hour?

Suppose you are starting counting number of right angles from midnight 12:00 clock.

Then in first 12 hours.

All hour makes a right angle 2 times except starting 12:00 clock and ending 11:00 clock only-only 1 time.

That's why in 12 hours it is 22 times. And in 24 hours it is 44 times.

How many time the hands of a clock are at right angle between 1pm to 10pm?

My answer contradicts nearly everyone! I make it 45 hits at 90 degrees separation in 24 hours.

Starting at 3.00 am we have our first hit. The second one occurs at just after 3.30 am because the hour hand has moved a little.

Repeating the process till we get to 9 are we end up with 12 hits in six hours.

The next hit is now hit 13, just after 9.30 am 11 more hits gets us back to 3.00 pm. 11 more back to 9 pm and a further 11 back to 3.00 am the next day. These add up to 45!

It is wrong to assume you just multiply the first 12 by 4 to get 48. In doing so you are counting 9am twice, 3pm twice 9pm twice thereby adding a further three on to the value of 45.

There is a flaw in the reasoning to get to 44, which seems to be the smart answer. I too tried it with a watch and verified 45 over and over.

Anyone agree with me?

How many times starting at 1:00pm would the minute and hour hands of a clock make an angle of 40 degrees with each other in the next 6 hours?

Can anyone answer this question?

Leonard: You need to start at 12.00, not 3.00, as a day starts at 12.00 - read the question :-)

Hey, guys, this might help. The 2nd right angle of 2'oclock will be 3'oclock already. Same as the 2nd right angle of 8'oclock. Therefore in 12 hours there's only 22 right angles.

I am giving SIMPLE EXPLANATION.

Yes, it's right that in each hour clock generally makes 2 right angles.

But between 2-4 it makes only 3 instead of 4 because, at 3 o clock, the right angle is common to both intervals of (2-3) and (3-4).

Similarly, 8-10 make 3 right angles.

ie, 22 right angles in 12 hours and 44 in a day.