Answer:
Joe is 14.
Martha is 28.
Explanation:
Use the variables and information from the question to make equations.
If Joe's age is half Martha's:
(1/2)m = j OR 2j = m
If their ages combined is 42:
m + j = 42
We can substitute the equation m=2j into equation m + j = 42, replacing "m".
m + j = 42 Substitute m for 2j
2j + j = 42 Combine like terms, terms with same varables
3j = 42 Divide both sides by 3 to isolate j
j = 14 Joe's age
Since j = 14, we can substitute it into equation m=2j to find "m".
m = 2j Substitute j for 14
m = 2(14) Simplify
m = 28 Martha's age
Therefore Joe is 14 and Martha is 28.