No poop Sherlock...................
Just volunteering a few hours a month can be a big help.
Option A.
<u>Explanation:</u>
The reason where Maxwell should focus on for finding the evidence is that volunteering only for some hours in the whole month by all the people can make a huge difference in total and increase the welfare activities for the whole society.
If evidence for this is found out for this reason, it will encourage the people to increase the amount of them volunteering for the social activities and working for the betterment of the society.
Let maggie's age be x
brother's age = 2x +3
24= 2x +3 +x
21 = 3x
x = 7