Final answer:
John's take-home pay for last month was $4,265.46.
Step-by-step explanation:
To calculate John's take-home pay, we need to subtract the deducted amount from his gross pay. The deducted amount is $421.78, so we subtract that from $4,687.24 to find John's take-home pay:
$4,687.24 - $421.78 = $4,265.46
Therefore, John's take-home pay for last month was $4,265.46.