math (discount)
posted by anonymous .
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?: *
$325
$375
$400
$425
Please explain, thanks

What's to explain?
(0.90)(0.85)P = $306
Solve for the original price, P 
The regular price was 400.00
400.0010%=360.00
360.0015%=306.00 
A woman saved $225 on the new sofa which was on sale for 30% off. WHat was the original price?