Question

Your company recently made a purchase of 25 identical tables. The purchase price after adding 5 percent sales tax was 1,706.25. You later realize that only need 20 tables. If you decided to return five tables, what would be the refund about before tax?

Answer 1

If c = the cost of one table, the cost of all 25 tables before sales tax is 25·c

Since the sales tax is 5%, or 0.05, the sales tax for 25 tables is 25·c·0.05

Adding the sales tax to the original cost of the 25 tables can give you:
25·c + 25·c·0.05 = 1706.25
1.05·25·c = 1706.25
26.25·c = 1706.25
c = $\frac{1706.25}{26.25}$ = 65

so the refund for 5 tables would be 5*65 = $325