| At what point of time after 3 0' clock, hour hand and the minute hand are at right angles for the first time? |
A) \[9\,\,\text{O}'\text{clock}\]
B) \[4\,\,\text{h}\,\,37\frac{1}{6}\min \]
C) \[3\,\,\text{h}\,\,30\frac{8}{11}\min \]
D) \[3\,\,\text{h}\,\,32\frac{8}{11}\min \]
Correct Answer: D
Solution :
| Clock will make right angle at \[(5n+15)\times \frac{12}{11}\min \]past n. |
| Given that, \[n=3\] |
| \[\therefore \]\[(5\times 3+15)\times \frac{12}{11}\min \,\,\text{past}\,\,3\] |
| \[=30\times \frac{12}{11}\min \,\,\text{past}\,\,3\] |
| \[=32\frac{8}{11}\min \,\,\text{past}\,\,\text{3}=\text{3}\,\,\text{h}\,\,\text{32}\frac{8}{11}\min \] |
You need to login to perform this action.
You will be redirected in
3 sec
