A house-owner was having his house painted. He was advised that he would require 25 kg of paint. Allowing for 15% wastage and assuming that the paint is available in 2 kg cans, what would be the cost of paint purchased, if one can costs Rs. 16?
Considering 15 % wastage,
85% is equivalent to 25 kg.
Therefore 100% is equivalent to $\frac{25}{85}*100$ = $\frac{500}{17} $ kg
Therefore no. of cans of paints to be purchased = $\frac{250}{17}$
Therefore required money= Rs. $\frac{250}{17}*16$
However, the answer is Rs. 240
25kg of paint are needed and it is estimated that 15% of the paint bought will be wasted...so the actual amount of paint needed is $$115 \%\cdot 25kg=28.75kg$$ Since each can contains 2kg of paint, the number of cans required is $28.75/2=14.375$ cans. Obviously you must round up to the the nearest whole number since you cannot buy a fraction of a can. So $15$ cans are required. So the cost is: $$15\cdot16=240$$