Clock and calender
- At what time between 8 and 9 o'clock will the hands of a clock be at right angle ?
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Consider exactly at 8 : 00, minute hand is at position '12' and hour hand is at '8' hence angle between these two hands at 8 : 00 is 240°.
Case (i) when minute hand is behind Hour hand then required time is (240 - 90)/(11/2) = 150/(11/2) = 300/11 = 27 3/11 minute
Case (ii) when minute hand is ahead of four hand then required time is (240 + 90)/(11/2) = 330/(11/2)
= 330 x 2/11 = 60 minute i.e., at 9 : 00 PMCorrect Option: B
Consider exactly at 8 : 00, minute hand is at position '12' and hour hand is at '8' hence angle between these two hands at 8 : 00 is 240°.
Case (i) when minute hand is behind Hour hand then required time is (240 - 90)/(11/2) = 150/(11/2) = 300/11 = 27 3/11 minute
Case (ii) when minute hand is ahead of four hand then required time is (240 + 90)/(11/2) = 330/(11/2)
= 330 x 2/11 = 60 minute i.e., at 9 : 00 PM
- At what time between 9 and 10 o'clock will the hands of a clock be in the same straight line but not together ?
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9 :164/11
Correct Option: A
9 :164/11
- Find the angle between minute hand and hour hand at 2 : 45
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From the formula the required angle is 187.5°
Correct Option: D
From the formula the required angle is 187.5°
- Find the percentage change in angle between minute hand hour hand from 2 PM to 6 PM.
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At 2 PM angle between minute hand and hour hand is 60° and that at 6 PM is 180° hence percentage change is 200%.
Correct Option: B
At 2 PM angle between minute hand and hour hand is 60° and that at 6 PM is 180° hence percentage change is 200%.
- Find the angle between minute hand and hour hand at 2 : 18 AM
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39°
Correct Option: C
39°
