Problem Solving

Question

Anna needed to let everyone in the music club know the time of its next meeting. She called two people and asked each of them to call two other people, and so on. If each phone call takes one minute, how many phone calls were made during the fifth minute?

Answer 1

You might try drawing a diagram, like a family tree type diagram. The first minute, Anna called two people (2).The second minute, each of those two people called two people (2x2). The third, each of those people that were called in the 2nd minute called two people, so (2x2)x2. Fourth minute, each of those people called two more, so multiply by two again to get (2x2x2)x2. Fifth minute, (2x2x2x2)x2 = 2⁵