Shapovalov A.V.

Petya liked the puzzle, he decided to glue it together and hang it on the wall. In one minute, he glued together two pieces (initial or previously glued). As a result, the entire puzzle was assembled into one complete picture in 2 hours. How long would it take to assemble the picture if Petya glued together three pieces per minute instead?

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Each gluing reduces the number of pieces on the table by 1. Since after 120 gluings, one piece (the complete puzzle) was obtained, there were 121 pieces before the work began. Now, if gluing three pieces together per minute (i.e., reducing the number of pieces by 2), one piece will remain after 60 minutes.

## Oтвет

In one hour.