Find all integers n such that when the clock strikes n o'clock, the acute angle between the hour and minute hands is 90 degrees. Enter your answer as a comma-separated list.

Guest Jul 14, 2021

#1**0 **

*< Find all integers n such that when the clock strikes n o'clock, the acute angle between the hour and minute hands is 90 degrees. Enter your answer as a comma-separated list. >*

Note that 90^{o} is __not__ an acute angle, but never mind that. When the clock strikes the hour, that means the minute hand is on the 12. For the angle to be 90^{o} the hour hand must be on either the **3** or the **9**. Assuming a 12-hour clock.

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Guest Jul 14, 2021