SOLUTION: A clockmaker makes a 12-hour clock but with the hour and minute hands identical. An ambiguous time on this clock is one where you cannot tell what time it is, since the exact posit

Algebra.Com
Question 1182848: A clockmaker makes a 12-hour clock but with the hour and minute hands identical. An ambiguous time on this clock is one where you cannot tell what time it is, since the exact position of the two hands occurs twice in a 12-hour cycle.
For instance, the clock can show 7:23 pm and 4:37 pm so both of these times are ambiguous.
However, 12:00pm is not ambiguous, since both hands are together.
How many ambiguous times happen in the 12 hours from midday to midnight?

Found 2 solutions by Boreal, ikleyn:
Answer by Boreal(15235)   (Show Source): You can put this solution on YOUR website!
There would be 11 of them, one after each hour, and the eleventh would occur at midnight.
Answer by ikleyn(52855)   (Show Source): You can put this solution on YOUR website!
.
A clockmaker makes a 12-hour clock but with the hour and minute hands identical.
An ambiguous time on this clock is one where you cannot tell what time it is,
since the exact position of the two hands occurs twice in a 12-hour cycle.
For instance, the clock can show 7:23 pm and 4:37 pm so both of these times are ambiguous.
However, 12:00pm is not ambiguous, since both hands are together.
How many ambiguous times happen in the 12 hours from midday to midnight?
~~~~~~~~~~~~~~~~~


If I do understand the problem and the question correctly, ambiguous moments are those 
when the minute hand and the hour hand are symmetric about the vertical line 12:00 - 6:00.


In 12 hours from midday to midnight, these moments happen when the hour hand is between  

   1)  12:00 and 1:00;     2)  11:00 and 12:00

   3)   1:00 and 2:00;     4)  10:00 and 11:00

   5)   2:00 and 3:00;     6)   9:00 and 10:00

   7)   3:00 and 4:00;     8)   8:00 and  9:00

   9)   4:00 and 5:00;    10)   7:00 and  8:00

   11)   5:00 and 6:00;   12)   6:00 and  7:00


So, if I presented it correctly, it happens 12 times, if the midday and midnight are excluded  ("strictly between"),

and  12 + 2 = 14 times, if the midday and midnight are included.

The problem does not ask to determine these time moments  PRECISELY,  so I do not compute them.
It  ONLY  asks  " how many such moments do happen ",  and  I answered it.


Strictly between midday and midnight,  it happens one time each hour.


////////////


By the way, there is another set of ambiguous configurations, when both hands are in one straight line with opposite directions.

It adds another 11 time moments between the midday and midnight, when you can not distinct / (determine) the correct time.



RELATED QUESTIONS

What is the smaller angle in degrees between the hour and minute hands of a clock at... (answered by Alan3354)
A clock has hour and minute hands 1 and 1.6 inches long respectively. At what rate are... (answered by robertb,ikleyn)
At 2:15 o'clock the hour and the minute hands of a clock form an angle of... (answered by MissionPossible)
At 2:15 o'clock the hour and the minute hands of a clock form an angle of degrees (answered by smaraya)
Between the times 830 am and 3:30 pm, how many times will the hour and minute hands form... (answered by Fombitz)
Can you help me with this question, please? A clock shows the time 12:40 The hour... (answered by josmiceli)
I am an adult who is reviewing my high school algebra II course from many years ago. I... (answered by solver91311)
The lengths of the hour and minute hands of a clock are 4cm and 6cm respectively. What is (answered by ikleyn)
Find the exact angle measure between the minute and the hour hands at 1:22 PM of a... (answered by josmiceli)