Kamal bought a house, whose sale price was Rs. 8 lakh. He availed 20% discount as an early bird offer and then 10% discount due to cash payment. After that he spent 10% of the cost price in interior decoration and lawn of the house. At what price should he sell the house to earn a profit of 25%?

Answer: Option C

Let the marked price be 100
100 == 20% ↓(discount) ⇒ 80 == 10%↓ (discount) ⇒ 72(CP) == 10%↑ (interior) ⇒ 79.2(Total CP)
Now, selling price would be 25% above the Total cost price.
SP = 79.2 + 25% of 79.2
SP = 99
Now, On comparing,
100 ⇒ 800000
99 ⇒ $$\frac{800000}{100}\times 99$$    ⇒ 7,92,000
So,
SP = Rs. 7,92,000