Question 389939
Let {{{x}}} = gallons of fresh water to be added
In words:
(salt in sea water already present)/(gallons of sea water + fresh water added) = 7%
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given:
gallons of sea water = {{{200}}}
gallons of salt in sea water = {{{.075*200 = 15}}}
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{{{ 15/(200 + x) = .07}}}
{{{15 = .07*(200 + x)}}}
{{{15 = 14 + .07x}}}
{{{.07x = 1}}}
{{{x = 14.285}}} gallons
14.285 gallons of fresh water should be added
check:
{{{15/214.285 = .07}}}
{{{.07 = .07}}}