Why do you have to include the opportunity cost of your time when you calculate your profits in your own business

Tom has brought $150,000 from his pension to a new job where his employer will match 401(k) contributions dollar for dollar. each year he contributes $3,000. after seven years, how much money would tom have in his 401(k)?

What is used by accountant to analyze transactions ?

The petty cash fund has a current balance of $ 350, which is the established fund balance. based on activity in the fund, it is determined that the balance needs to be changed to $ 450. which journal entry is needed to make this change?