Total investment=$2500
Let say David earned 5% profit and Harry earned 3% profit.
If David invested y dollar in mutual fund then Harry would invest,
Harry would invest,$(2500-y)
Total profit would equal to sum of 5% of money David invested and 3% of money Harry invested,
So,
5% × y +3% ×(2500-y)=total profit
0.05×y+0.03×(2500-y)=$111
0.05y+0.03×2500-0.03y=111
0.02y+75=111
0.02y=111-75
y=36/0.02
y=$1800
which is the amount David invested.
The amount invested by Harry would be,
=$(2500-1800)
=$700
