Problema Solution

A mixture of water and antifreeze is currently 20% antifreeze. If the radiator holds 5 gallons of fluid and this mixture should be 40% antifreeze, how many gallons of fluid should be drained and replaced with a mixture containing 90% antifreeze?

Answer provided by our tutors

Let 'x' represent the number of gallons that should be drained and replaced with 90% antifreeze.

(5 - x)*0.20 + x*0.90 = 0.40*5

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click here to see the equation solved for x

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x = 1.43 gal

1.43 gallons should be drained and replaced with 90% antifreeze.