How many litres of a 30% alcohol solution should be added to 40 litres of a 60% alcohol solution to prepare a 50% solution ?
A. 20
B. 24
C. 30
D. 32
Answer: Option A
Solution (By Examveda Team)
Let x litres of 30% alcohol solution be added.Then, 30% of x + 60% of 40 = 50% of (x + 40)
⇒ 30x + 60 × 40 = 50 (x + 40)
⇒ 30x + 2400 = 50x + 2000
⇒ 20x = 400
⇒ x = 20
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