Correct Answer - Option 1 : 28.8%
Let the original price of paint be 100x units
Let the original cost of labor be 100y units
According to the question,
Total cost of painting the room is directly proportional to the product of price of paint to the labour cost
Original cost of painting the room = 100x × 100y = 10000xy
Price of paint is increased by 12%
New price of paint = 100x + 12% of 100x = 112x
Cost of labour is increased by 15%
New cost of labour = 100y + 15% of 100y = 115y
New cost of painting the room = 112x × 115y = 12880xy
Increase in the cost of painting the room = 12880xy – 10000xy = 2880xy
Required percentage = {(Increase in cost)/(original cost)} × 100
Required percentage = (2880xy/10000xy) × 100 = 28.8%