PROBLEM 4

My toaster oven is broken. It will only toast bread on one side at atime. It holds two slices at a time but, since the door is broken, I only haveone free hand so I must place the slices in the oven one at a time. Nor is itpossible to turn two slices over simultaneously. I also want to butter my toaston one side. Once again, it is not possible to butter a slice while another isbeing put into the toaster, turned over, or taken out.

It takes 3 seconds to put a slice in the toaster, 3 seconds to turn it over, and3seconds to take it out. It takes 30 seconds to toast a slice on one side and ittakes 12 seconds to butter a slice.

Each slice is buttered on one side only and a side may not be buttered before itis toasted. A slice may be toasted and buttered on one side and then returnedfor toasting on the other side.

What is the minimum time required to toast and butter three slices according tothese restrictions?

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