Step-by-step explanation:
Hey there!
The amount deposited= $1800
And it's just 20% of total monthly amount.
Let total amount be "x".
Then;
$1800 = 20% of X
[tex]1800 = \frac{20}{100} \times x[/tex]
or, 180000= 20x
or, X = 180000=/20
Therefore, total monthly amount or income was $9000.
Hope it helps!