Answer:
$29.14
$86.68
Explanation:
$30 before tax
Discount: 20%
100% - 20% = 80% = 0.8
0.8 * $30 = $24 after discount
Tax: 6.4%
100% + 6.4% = 106.4% = 1.064
1.604 * $24 = 25.54 after tax and discount
Tip: 15% = 0.15
0.15 * $24 = $3.60
Total = $25.54 + $3.60 = $29.14
$75 before tax
10% discount
100% - 10% = 90%
90% of $75 = 0.9 * $75 = $67.50 after discount
Tax: 7%
100% + 7% = 107% = 1.07
1.07 * $67.5 = $72.23 after discount and tax
Tip: 20% = 0.2
0.2 * $67.50 = $13.50
Total = $72.23 + $13.50 = $85.73