Question

You need to make five grilled cheese sandwiches. You have a grill that is large enough to toast two sandwiches at a time. The sandwiches must be toasted one minute on each side. It takes 3 seconds to flip a sandwich and 5 seconds to take one off or put one on the grill. What is the shortest amount of time needed to toast all five sandwiches?

Answer 1

First two sandwiches are on the grill for 60 secs, then flip both of them will take 6 secs, continue grilling for another 60 secs. So total so far 126 secs. Take out grilled sandwiches and put two new sandwiches take 20 seconds ( i assume we can only work on one sandwich each time). Then grill for 60 secs, flip the sandwiches and grill 60 secs. So total 266 secs is gone. Take out the sandwiches and put the last sandwich take 15 secs. Now total is 281 secs. Grill for 60 secs, flip it and grill another 60 secs and take it out take 131 secs. Therefore grand total is 412 secs which is 6 mins 52 secs.
Is this the right way to grill the sandwiches?