Question

A school with 60 teachers is on alert during a nighttime storm. To inform teachers whether the school will open the next day, the principal will call four teachers, each of whom will call two others, and each of these will call two others, and so on until all 60 teachers have been contacted. How many teachers will have to make two calls?

A) 32
B) 29
C) 16
D) 24
E) 28

Answer 1

The answer is 16

Explanation:

call four teachers, each of whom will call two others, and each of these will call two others

Answer 2

E) 28

Explanation:

The 4 teachers the principal calls will each make 2 calls.

The 8 teachers they call will each make 2 calls.

The 16 teachers they call will each make 2 calls. At this point, all 60 teachers have been notified, and the last 32 recipients of calls don't need to call anyone.

4 +8 +16 = 28 teachers make 2 calls.