1) A rectangular room of size 5mX4mX3m is to be painted.If the unit cost of painting is Rs.10 per sq.m, what is the total cost of painting? A) Rs.940 B) Rs.740 C) Rs.640 D) Rs.800 Answer: Option BExplanation:Area of 4 walls= 2h(l+b) The area to be painted includes the 4 walls and the top ceiling. Total area to be painted$=2h(l+b)+lb$ $=2\times 3(5+4)+5\times 4$ $54+20=74 sq.m$ Total cost of painting $=74\times 10=Rs.740$
