A dishonest milkman wants to make a profit on the selling of milk. He would like to mix water (costing nothing) with milk costing Rs.33 per litre so as to make a profit of 25% on cost when he sells the resulting milk and water mixture for Rs.36 In what ratio should he mix the water and milk?  Choose the correct choice:
A) 1:20
B) 1:10
C) 1:8
D) 1:4
E) 21:124
water = w (liter)   Milk = m (liter)   ==&gt; Cost = Price x Quantity = 0.33m   ==&gt; Revenue = Price x Quantity = 0.36(m + w)   ==&gt; Profit =0.36(m+w) - 0.33m = 0.25*(0.33m)[25% of cost]   ==&gt; 0.36m + 0.36w - 0.33m = 0.0825m   ==&gt; 0.0525m = 0.36w   ==&gt; m/w = 0.36/0.0525 = 124/21   --OR--   w/m = 21/124   21:124 is correct.
<result>E</result>
A dishonest milkman wants to make a profit on the selling of milk. He would like to mix water (costing nothing) with milk costing Rs.33 per litre so as to make a profit of 25% on cost when he sells the resulting milk and water mixture for Rs.36 In what ratio should he mix the water and milk?