How to i solve for x (original price)?

Question

An instrument store gives a 10% discount to all students off the original cost of an instrument. During a back to school sale an additional 15% is taken off the discounted price. Julie, a student at the local high school, purchases a flute for $306. How much did it originally cost?

Answer 1

10% diskount meen kost=90%...0.90 times original kost

xtra 15% from that...0.85*0.9=0.765 times start pries

end kost=306$

start pries=306$/0.765=400$