Answer:
11
Explanation:
You have to make a system of equations. So the first equation would be b=2m-4 (b is brother m is maggie). The next equation is 29=m+b (sum of their ages). Then you can use substitution so plug in 2m-4 for b in the second question. So it would be 29=m+2m-4. Simplify and solve for m and you get 11.