Question

Three slices of bread are to be toasted under a grill. The grill can hold two slices at once but only one side is toasted at a time. It takes 30 seconds to toast one side of a piece of bread, 5 seconds to put a piece in or take a piece out and 3 seconds to turn a piece over. What is the shortest time in which the three slices can be toasted?

Answer 1

159 seconds. The 1st two slices of bread will take 60 seconds to toast. 20 second to put in and out. And 6 seconds to turn them over. The 3rd piece will take 60 seconds to toast, 10 seconds to put in and out, and 3 seconds to turn over. 86 seconds + 73 seconds= 159