What is the adverbial phrase in when you've finished,do the extra questions on page one

When you've finished
When you've finished
When you've finished
When you've finished
When you've finished
When you've finished
When you've finished
When you've finished

We know from the question that Store A charges $1200 for repairs and 6% as sales tax.
Then
Amount of sales tax charged by Store A = (6/100) * 1200
                                                                 = 6 * 12
                                                                 = 72 dollars
Then the total amount charged by Store A = ( 1200 + 72) dollars
                                                                   = 1272 dollars
Now coming to Store B. It charges $1350 for repairs and 7% of sales tax.
Amount of sales tax charged by Store B = (7/100) * 1350
                                                                 = 945/10
                                                                 = 94.5 dollars
Then the total amount charged by Store B = ( 1350 + 94.5) dollars
                                                                     = 1444.5 dollars
Amount of money saved by choosing Store A instead of Store B = (1444.5 - 1272) dollars
                                                                                                       = 172.5 dollars
So $172.5 is saved by choosing Store A over Store B.