Accounts Spreadsheet - Formula for working out amount deductions

Hi all,

I hope this is the correct forum to post a question like this...

As captain of my rowing squad, part of my duties is to manage the accounts for race entrie fee's for each squad member. As such, I have put a spread sheet together using Google Sheets so that everyone has a full account of how much they have remaining, along with the cost of each race. As the season goes on, their account diminishes, and we can see at a glance just how much they have remaining.

In the attached snip, you can see I have worked out the following:

Google Sheets - MT2 Accounts.PNG

I entered £50 into cell B8. If cell C8 reads the word "Yes", the cost in cell C6 is deducted, resulting in the sum of £37.50 - the remaining balance. What I would like to do is apply the same to D, E, F, and G, but keep the value in B8 the same after any deductions for the previous race.

Any ideas what forumla I would need to use?

Many thanks in advance!