Answer: Karl's net income is 48,750
This does not count state and local taxes, but those are not part of this question.
Explanation:
Multiply 65000 × 0.18 to find the federal income tax: $11,700
Multiply 65000 × 0.07 to find the social security tax: $4550
Add those together to find the total tax to be subtracted from his gross income:
11700 + 4550 = 16250
$65,000 - $16,250 = $48,750