Let X be the total amount of Ava's paycheck.
According to the problem, Ava spent 15% of X at the mall, so:
0.15X = $48
Solving for X, we get:
X = $48 / 0.15
X = $320
Now, we know that 35% of X was saved, so:
0.35X = 0.35 * $320
0.35X = $112
And we also know that 45% of X was spent on bills, so:
0.45X = 0.45 * $320
0.45X = $144
Finally, we can calculate the amount donated to charity by subtracting the amounts spent on bills, saved, and spent at the mall from the total paycheck:
Amount donated to charity = X - (0.15X + 0.35X + 0.45X)
Amount donated to charity = $320 - ($48 + $112 + $144)
Amount donated to charity = $16
Therefore, Ava donated $16 to charity.