Step-by-step explanation
From the statement, we know that the store:
0. buys instruments and then sells them for 30% more than they paid,
,
1. during a 20% sale, the store offers a clarinet for $93.60.
(1) From point 1, we know that the relation between the original price (Po) and the selling price (Ps) is given by:
(2) From point 2, we know that the relation between the final price with the discount (P_f) and the selling price without the discount (Ps) is:
(3) Finally, replacing the value of Ps in the equation of point (1), we find that the original price of the instrument was:
Answer
The store paid approximately $90 for the clarinet.