Question

Mona has 20 lbs of 20% sugar syrup. How much pure water should she add to make 16% sugar syrup?

Answer 1

5 lbs

Explanation:

Let x lbs be the amount of pure water that should be added. Then the new sugar syrup will have x+20 lbs.

In 20 lbs of 20% sugar syrup there are
`20\cdot 0.2=4` lbs of sugar. This amount of sugar will remain in nwe sugar syrup the same. So

x+20 lbs - 100%,

4 lbs - 16%.

Write a proportion:

`(x+20)/(4)=(100)/(16),\\ \\16(x+20)=4\cdot 100,\\ \\16x+320=400,\\ \\16x=80,\\ \\x=5\ lbs.`