Please solve ques no-12

Dear student
Length (l)=10m
Breadth(b) = 5m
Height (h)= 6m
Area of 4 walls is 2(l+b)h
=2x15x6 m² 
=180 m²
Per m²  cost =₹4
For 180 m²
=180x4
=720₹
The cost of Painting is 720₹ 
Regards