With 630 ml mixture of milk & water in the ratio 7:2. How much water mustbe added to make the ratio 7:3?
Choose the correct choice from the following answers:	A) 60 ml	B) 80 ml	C) 70 ml	D) 90 ml	E) 92 ml
concentration of water in mixture1   =2/9 (since the ratio of milk and water = 7:2) ...(1)   concentration of water in pure water= 1 ...(2)   Now the above mentioned items are mixed to form mixture2 where milk and water ratio = 7 : 3   =&gt; concentration of water in mixture2   =3/10   By rule of alligation,   concentration of water in mixture1   (2/9) concentration of water in pure water (1)   Mean concentration   (3/10)   1−3/10=7/10   =1:19   =&gt; Quantity of water   =630×1/9=70 ml   70 ml
<result>C</result>
With 630 ml mixture of milk & water in the ratio 7:2. How much water mustbe added to make the ratio 7:3?