A house owner was having his house painted. He was advised that he would require 30 kg of paint. Allowing for 20% wastage and assuming that the paint is available in 3 kg cans, what would be the cost (in Rs.) of paint purchased, if one can was priced Rs.10?
130
Paint under use = 80% = 0.8 of X [if X is the total paint bought]
0.8 X = 30
X = 37.5kg => number of cans required = 13.
Thus, cost = 13×10 = Rs.130