Let's say the deposit number is z.
$87.75 is 4.5% of 3z.
"of" is multiplication.
So, it would read $87.75 is 4.5% x 3z.
Change the percentage to a decimal (without it being a percentage).
It would then read $87.75 is 0.045 x 3z.
The opposite of multiplication is division, so instead of multiplying 0.045 by 3z, you would divide $87.75 by 0.045 to equal 3z.
This would equal 1,950 = 3z.
Now, just like in an algebraic equation, you would divide both sides by 3.
1,950/3 = 3z/3
650 = z
$650 is the deposit amount.
