How much water should be added to a 30 L mixture of milk and water, which currently has a ratio of 7:3, so that the resultant mixture contains 40% water?
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4, i.e., 5 l.
Let water be added = x L
Water now = 30 × 3/10 = 9 L
Total mixture after adding water = 30 + x L
(9 + x)/(30 + x) = 40/100
100(9 + x) = 40(30 + x)
900 + 100x = 1200 + 40x
60x = 300
x = 5 L