Answer:
She gained $ 10.
Step-by-step explanation:
Given,
The initial amount Maria's account = $ 50
Let x be the additional amount for the month,
So, at the end of the month the balance of account = ( 50 + x ) dollars,
According to the question,
50 + x = 60
⇒ x = 10,
Positive sign shows there is a gain.
Hence, the amount she gained is $ 10.