Since no value is given to Eva, we'll call her x. Justin, then, is 7.50+x. That leaves Emma, who would be Justin (7.50+x) -12. If we add them all together we get 63. So our equation is
x + (7.50+x) + (7.50+x)-12 = 63
Combine like terms
x+x+x + 7.50+7.50-12 = 63
3x + 3 = 63
3x = 60
x = 20
Since we said Eva is x then Eva has 20 dollars.
Justin is 7.50 + x so 7.50+20=
$27.50
Emma is Justin - 12 so 27.50-12= $15.50
Let's check our answer...
15.50+27.50+20 = 63
63=63
It checks!
