The sum of two numbers is 47. One of the numbers is 2 more than twice the other number. Find the value of the smaller number.

Question

Selected applications of linear equations

Answer 1

Thorough is nice for practice, practice, practice.  For a test, think triage!

 

S + (2S + 2) = 47

       3S = 45

        S = 15

 

If you are practicing, go ahead and find L; for a test, quickly move on!   (there is no extra credit for TMI)

Answer 2

you can also use two variables and solve by substitution:

 

Let L be the larger number and S be the smaller number

 

L+S=47

L=2S+2

 

Substitute for L:

(2S+2)+S=47

3S+2=47

3S=45

S=15

 

The smaller number is 15 an the larger number is 32

Answer 3

s = smaller number

2s + 2 = larger number

 

s + 2s + 2 = 47

3s + 2 = 47

3s = 45

s = 15

.

The two numbers are 15 and 32.