Correct Answer: Rs. 6000
Explanation:
Total are of all stairs = 50 (20x60 + 30x60)
= 50 (1200 + 1800)
= 50 x 3000
= 150000 sq cm.
Given rate of 100 sq cm = Rs. 4
Then for 150000 sq. cm = ?
=> 4 x 150000/100 = Rs. 6000