How much pure alcohol should be added to 400ml of a 15% solution to make the strength of solution 30%?  Choose the correct choice from the following choices
A) 100 ml	B) 60 ml	C) 120 ml	D) 130 ml	E) 150 ml
we can also go by answer choices   Tke 100 ml for eg   400 (old)+100 (new concentr)ml     500*30/100= 
<gadget id="calculator">  500*30/100</gadget>
<output>150</output>
150 ml (50ml is de old concentration +100 ml (newly added)   Answer 150 ml
<result>E</result>
How much pure alcohol should be added to 400ml of a 15% solution to make the strength of solution 30%?