Martha is buying two shirts that each cost $20. She is considering two options to purchase the shirts. Option A: use the store sale buy one shirt and get the second shirt at 50% off the original. Option B is use a 30% off coupon for the entire purchase. Martha will also pay 7% tax on her purchase. Which option will cost less?
Option A: If Martha buys one shirt at full price ($20), she will get the second shirt at 50% off, so she will pay 50% of $20 which is $10. The total cost for the shirts without tax is $20 + $10 = $<<20+10=30>>30.
Option B: If Martha uses a 30% off coupon, she will receive a discount of 30% of $40 (the total price of both shirts at $20 each). The discount is 30/100 * $40 = $<<30/100*40=12>>12. The total cost for the shirts without tax is $40 - $12 = $<<40-12=28>>28.
Now, Martha needs to calculate the amount of tax on each option. For option A, the tax is 7% of $30 which is 7/100 * $30 = $2.10. For option B, the tax is 7% of $28 which is 7/100 * $28 = $1.96.
Adding the tax to each option, the total cost for option A is $30 + $2.10 = $<<30+2.10=32.10>>32.10 and the total cost for option B is $28 + $1.96 = $<<28+1.96=29.96>>29.96.
Therefore, option B (30% off coupon) will cost less than option A (50% off second shirt) when considering the tax.