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

The answer is 16

Step-by-step explanation:

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

  E) 28

Step-by-step 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.

(0,-3) see attached graph

step-by-step explanation:

a. to solve the system, graph the two equations.

x = y+3 becomes y=x-3 has m=1/1 and b=-3. start at (0,-3) on the y-axis and plot a point. then move up 1 unit and 1 unit to the right. plot a point and connect.

y=-4x+3 has m =-4/1 and b=-3. start at (0,-3) on the y-axis and plot a point. then move down four units and to the right 1 unit. plot a point and connect.

the solution is the point (x,y) where the two lines intersect. by the graph below it is (0,-3).

b. to solve by substitution, substitute y = -4x-3 into x= y+3

x= (-4x-3) +3

x=-4x

5x=0

x=0

now substitute x = 0 back in to find y.

y= -4(0)-3

y=0-3

y=-3

solution is (0,-3)

c. use elimination by adding the equations together.

x-y=3

4x+y=-3

5x=0

x=0

then substitute into one equation to find y.

y=-4(0)-3

y=-3

the volume is the product of the area of the base, 3x(3x+4), and the height, 3x-1

step-by-step explanation: