Task 1. We put a strip from strips From five strips 1×n where n is odd number, one long strip 1×5n is put. It turned out that the average cage of the small strip second (at the left) is 20 - oh (at the left) in a long strip. Find 5n.

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Let p =2m+1. The middle of the 2nd strip is the 20th at the left in a long strip at the left. For the first time to a strip 2m+1 cages, and the second strip too 2m+1 cages, will have a middle cage (2m): 2+1=m+1. We receive: 2m+1+m+1=20.reshim: 3m=18.m=6. Means, p =2×6+1=13. Then 5n=5*13=65.answer: 65.
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