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 School time (Posted on 2004-02-07)
A boy leaves home in the morning to go to school. At the moment he leaves the house he looks at the clock in the mirror. The clock has no number indication and for this reason the boy makes a mistake in interpreting the time (mirror-image). Just assuming the clock must be out of order, the boy cycles to school, where he arrives after twenty minutes. At that moment the clock at school shows a time that is two and a half hours later than the time that the boy saw on the clock at home.
At what time did he reach school?

 See The Solution Submitted by Ravi Raja Rating: 2.4000 (5 votes)

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 there are 2 valid answers (or even 4) | Comment 3 of 8 |
both 7:25 (either AM or PM)
and 1:25 (either AM or PM) qualify as MATHEMATICAL valid ANSWERS for T.O.A.

Clearly the minutes must be :05
and the hours H0+HA=11 mod 12 i.e. 11,23,35..
& HA-HO=3
HA- hour of arrival HO- hour of observation

solving we get 4 answers within the 24 hour interval: 1, 7, 13, 19

however the boy leaves in the morning and this constraint voids all the answers
save 7:05 for leaving home = 7:25 for arriving to school.

 Posted by Ady TZIDON on 2004-02-07 12:26:14

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