999 - 99.90 (10% OFF) = ₹899.10

761.95 + 137.15 (18%) = 899.10

• 4 + @ 15% : 723.85 + 18% = 854.14
• 8 + @ 19% : 685.75 + 18% = 809.19
• 12 + @ 24% : 647.66 + 18% = 764.23