A dishonest person wants to make a profit on the selling of milk. He would like to mix water (costing nothing) with milk costing 33 $ per litre so as to make a profit of 70% on cost when he sells the resulting milk and water mixture for 36$. In what ratio should he mix the water and milk?	Choose the correct answer
A) 1:120 B) 67:120 C) 67:8 D) 8:120 E) 1:2
First of all, let's consider 1 liter of the stuff he is going to sell --- naive customers think it's pure milk, but we know it's some milk-water mixture. He is going to sell this liter of milk-water for $36.   This $36 should be a 20% increase over cost. Here, we need to think about percentage increases as multipliers.   Using multipliers   (cost)*1.70 = $36   cost = 36/1.7= 360/12= 
<gadget id="calculator">360/12</gadget>
<output>30</output>
$30   If he wants a 70% increase over cost on the sale of one liter of his milk-water, the cost has to be $21.17   Well, a liter of milk costs $33, so if he is going to use just $30 of milk in his mixture, that's 21.17/33= 120/187 of a liter. If milk is 120/87 of the liter, then water is 67/187 of the liter, and the ratio of water to milk is 67:120. Answer choice(67:120)
<result>B</result>
A dishonest person wants to make a profit on the selling of milk. He would like to mix water (costing nothing) with milk costing 33 $ per litre so as to make a profit of 70% on cost when he sells the resulting milk and water mixture for 36$. In what ratio should he mix the water and milk?