Answer:
5 lbs
Step-by-step 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 [tex]20\cdot 0.2=4[/tex] 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:
[tex]\dfrac{x+20}{4}=\dfrac{100}{16},\\ \\16(x+20)=4\cdot 100,\\ \\16x+320=400,\\ \\16x=80,\\ \\x=5\ lbs.[/tex]
