Answer:
<em>$120</em>
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
Answer:
See below
Step-by-step explanation:
c = (a^2 + 3b) / 4 multiply both sides by 4
4c = a^2 + 3b subtract a^2 from both sides
4c - a^2 = 3b now divide both sides by 3
(4c-a^2) / 3 = b