Answer:
$900
Explanation:
Given:
Gwen's savings this month = 0.15(x + 500)
where,
x = last month's income.
Gwen saves $210 this month
What was Gwen's income in dollars last month?
Gwen's savings this month = 0.15(x + 500)
210 = 0.15(x + 500)
210 = 0.15x + 75
210 - 75 = 0.15x
135 = 0.15x
x = 135 / 0.15
= 900
x = $900
Gwen's income in dollars lat month = $900