Alligation or Mixture problems
From a container of wine, a thief has stolen 15 litres of wine and replaced it with same quantity of water. He again repeated the same process. Thus, in three attempts the ratio of wine and water became 343 : 169. The initial amount of wine in the container was:
w i n e ( l e f t ) w i n e ( a d d e d ) = 343 169 It means w i n e ( l e f t ) w i n e ( i n i t i a l a m o u n t ) = 343 512 (since 343 + 169 = 512) Thus, 343 x = 512 x 1 - 15 k 3 343 512 = 7 8 3 = 1 - 15 k 3 1 - 15 k = 7 8 = 1 - 1 8 Thus the initial amount of wine was 120 liters.
Here total parts of milk and water in the solution is 6+2 = 8 parts. 1part = 640/8 = 80 old mixture contains 6parts of milk and 2 parts of water(6:2). To get new mixture containing half milk and half water, add 4parts of water to the old mixture then 6:(2+4) to make the ratio same. i.e, 4 x 80 = 320 ml.
Let C.P. of 1 liter milk be Re. 1, Gain = 16 2/3 % = 50/3 %and S.P. of 1 liter mixture = Re. 1 then C.P. of 1 liter mixture = (1 x (100 x 3) / 350) = Re. (6 / 7) By the rule of alligation,Hence, required ratio = (1/ 7) : (6 / 7) = 1 : 6
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