First subtract 30-23 that’d be the value of UV(7) now subtract 18 from 7, the answer will be 11 therefore TU is 11.
Best to write these two figures in a column:
$5672
-$4523
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$ 1149 is the amount you have left.
7.50 X 315 =2362.50 at the lower price
7.75 X 315 = 2441.25 at the higher price
subtract 2362.50 from 2441.25 you get 78.75
