Question

How many quarts of water must be added to 7 qts of a 19% saline solution to obtain a 5% saline solution?

Answer 1

Answer: quantity of water added = 19.6 quarts

Step-by-step explanation:

Let x= quantity of water added

Then, Quantity of saline in 7 quarts solution  = 19% of 7 = 0.19 (7)=1.33 quarts [to remove % divide number by 100]

When x quarts water is added , the quantity of solution becomes = x+7

Quantity of saline in it= 5% of (x+7)= 0.05(x+7)

Now, quantity of saline remains same, so

$1.33= 0.05(x+7)\\\\\Rightarrow\ 1.33x=0.05x+0.35\\\\\Rightarrow\ 1.33-0.35=0.05x\\\\\Rightarrow\ x=\dfrac{0.98}{0.05}=19.6$

Hence,  quantity of water added = 19.6 quarts