Brain Teaser #54

Greg Bernhardt

Jack has an antique cuckoo clock. It's a lovely clock, but it runs too slowly; it loses 9 minutes of time every hour. Sam visits his friend Jack one day, and notices that the cuckoo clock is exactly on time at noon on Tuesday.
When is the next time Jack' clock will be exactly on time?

brum

4 am the following tuesday (6 days, 16 hours later)

marcus

in 80 hours from noon tuesday, they should agree

I suppose that is some time friday, 8 PM

Greg Bernhardt

marcus gets the point!