Answer:
$120
Step-by-step explanation:
40% of the earnings is spent on rent.
The earnings is an unknown, so we call it x.
The rent is $800, so 40% of x equals $800.
40% * x = 800
0.4x = 800
x = 800/0.4
x = 2000
She earns $2000 per month.
After paying rent, the remaining amount is
$2000 - $800 = $1200
She spends 10% of the remaining amount on entertainment.
10% of $1200 = 10% * $1200 = 0.1 * $1200 = $120
