First find how much the store makes in profit: $20 * 0.30 = $<<20*0.30=6>>6 for profit
Then find the regular selling price: $20 + $6 = $<<20+6=26>>26 total price
Then multiply the regular price by the discount to get $26 * 0.50 = $<<26*0.50=13>>13 for the final price
#### 13