To find Ben's new balance after the deposit:
- His account was overdrawn by $10, which can be represented as \(-10\).
- He then deposited $50 into his account.
The calculation can be set up as follows:
\[ -10 + 50 \]
Calculating that gives:
\[ 50 - 10 = 40 \]
Therefore, Ben's new balance is \( $40 \).