It can't be seen, can't be felt, can't be heard and can't be smelt. It lies behind stars and under hills, and empty holes it fills. It comes first and follows after, ends life and kills laughter. What is it?
Susan uses a toaster that has 2 slots. The toaster toasts one side of each piece of bread at a time, and it takes exactly 1 minute to do so.
If Susan wants to make three pieces of toast, what is the LEAST amount of time she needs to toast them on both sides?
She puts two pieces in the toaster, toasting one side of each. Then she flips one of them, takes one out, and puts the completely untoasted piece into the toaster. Finally, she takes out the toasted piece and puts the two half-toasted pieces of bread into the toaster for a minute and she's done.