Math Is Fun Forum

Nasir Hassan

Member

Registered: 2020-04-11

Posts: 6

Clock in the Mirror Puzzle

Your answer:                           
Time at club 7H25, time at mirror image home clock 2H30 earlier is 4H55       
Test: Actual time at home when he left is 7H05.  This gives club time 7H25 after 20min       
                               
What's wrong with this answer?                   
Time at club 13H25 (1:25pm), time at mirror image home clock 2H30 earlier is 10H55
Test: Actual time at home when he left is 13H05 (1:05pm). This gives club time 13H25 after 20 min.

I did it from 1st principles, but noticed the answer could have been extended intuitively from your answer by adding 6 hours to everything. Corrections? Comments?

Bob

Administrator

Registered: 2010-06-20

Posts: 10,621

Re: Clock in the Mirror Puzzle

hi Nasir,

Except the question starts "Joey leaves his house in the morning..."

So your time, after noon, won't fit.

Bob

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Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

Nasir Hassan

Member

Registered: 2020-04-11

Posts: 6

Re: Clock in the Mirror Puzzle

Hi Bob

Yep. 100%.  I missed that one cos I only got up in the afternoon!

Regards

Nasir

Nasir Hassan

Member

Registered: 2020-04-11

Posts: 6

Re: Clock in the Mirror Puzzle

Just to twist it a bit.  Could he have left at 1.25 in the morning??  Of course the mirror image would have told him it's the night before, but in reality he would have left in morning. Regards Nasir.

Bob

Administrator

Registered: 2010-06-20

Posts: 10,621

Re: Clock in the Mirror Puzzle

I missed that one cos I only got up in the afternoon!

Hhmm.  I see your point.  This would change your view on the puzzle.    But I don't think it's an allowable excuse for getting a different answer

Keep puzzling!

Best wishes,

Bob

---

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob