Answer:
$16
Explanation:
Let x = friends' donations
y = local chapter funds
4x = y
.8y = 51.2
Divide both sides by 0.8 for the second equation
.8y/.8 = 51.2/.8 = 64
Plug in the new y in the first equation
4x = 64
Divide both side by 4
4x/4 = 64/4
x = 16