Answer :
Let call the amount Kevin has x and the amount Diana has y.
The equations describing this situation are
[tex]x-16=y[/tex][tex]y-20=0.1x[/tex]Let us now solve the system.
The first equation gives us
[tex]x=y+16[/tex]putting this into the second equation gives us
[tex]y-20=0.1(y+16)[/tex]which simplifies to
[tex]y-20=0.1y+1.6[/tex]Combing terms gives us
[tex]0.9y=21.6[/tex]and dividing both sides by 0.9 gives us
[tex]y=24[/tex]And now we solve for x.
[tex]x=16+24[/tex]x = 40 and y =16
which is our answer!