Can you please show how did you got the overtime pay of $506.12? Thank You

Bob's annual package is $55,000, which equates to $2,291.67 per semi-monthly pay period. His vacation compensation is 6% of each payment, or $137.50 each month. For the 15 hours of approved overtime, he is paid 1.5 times his regular hourly rate, which comes to $506.25. Finally, his travel expenditures are reimbursed in the amount of $434.20. so, we will add up all these items