In this case, we'll have to carry out several steps to find the solution.
Step 01:
Data:
Earnings:
January = $2350
February = january + $500
March = twice as much (february)
Step 02:
March's earnings:
February = $2350 + $500 = $2850
March = 2 * $2850 = $5700
The answer is:
She earned $5700 in March