A solution of milk and water having 20% milk is mixed with another sol

Question

A solution of milk and water having 20% milk is mixed with another solution having 50% milk in the ratio 2 : 5. If 21 lts of this mixture is taken and mixed with 9 lts of another milk and water solution having 80% milk, find the percentage of milk in the final mixture.

1. 43 %
2. 47 %
3. 50 %
4. 53 %
5. 57 %

Show Answer

Official Answer

D

1. 43 %
 2. 47 %
 3. 50 %
 4. 53 %
 5. 57 %

gmatchile · Answer

Solution 20% milk : Solution 50% milk = 2:5
 
Then 7k = 21 lts
k = 3 lts

2k = 6 lts solution 20% milk, milk = (20/100) x 6 lts = 1.2 lts of milk
5k = 15 lts solution 50% milk, milk = (50/100) x 15 lts = 7.5 of milk
Total milk in 21 lts solution = 8.7 lts of milk

9 lts solution 80% milk = (80/100) x 9 lts = 7.2 lts of milk

21 lts (8.7 lts of milk) plus 9 lts (7.2 lts of milk)= 30 lts (15,9 lts of milk)

15 lts = 50% of 30 lts, 1% of 30 lts = 0.3 lts, 0.9 lts = 3% of 30 lts

Answer 4 = 53%

gmatchile 
 https://gmatchile.cl

A solution of milk and water having 20% milk is mixed with another sol

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