There are three numbers. The first number is twice the second number. The third number is twice the first number. The sum of the three numbers is 126.

Question

=126 

 

a. What is the first number?

b. What is the second number?

c. What is the third number?

Answer 1

Hello Emilee

 

Let f = the 1st #, s = the 2nd # and t = the 3rd #.

 

Eq 1) f = 2s

Eq 2) t = 2f

Eq 3) f + s + t = 126

 

Rearrange Eq 1) to solve for s gives s = f/2.  Now substitute this value of s, and Eq 2) into Eq 3), you get

 

f + f/2 + 2f = 126

 

Multiply both sides by 2

 

2f + f + 4f = 252

 

7f = 252

 

f = 252/7 = 36

 

s = f/2 = 36/2 = 18

 

t = 2f = 2 x 36 = 72

 

To confirm, f + s + t = 36 + 18 + 72 = 126!