89 - 8.90 (10% OFF) = ₹80.10

67.88 + 12.22 (18%) = 80.10

• 4 + @ 15% : 64.49 + 18% = 76.09
• 8 + @ 19% : 61.09 + 18% = 72.09
• 12 + @ 24% : 57.70 + 18% = 68.08