Question

275 gallons from a tank of 31% saline solution is drained and replaced with 500 gallons of 65% saline. What was the original volume of saline solution if the final saline concentration in the tank is 50%? Round your final answer to 1 decimal place if necessary.

Answer 1

Let

x -----> original volume of saline solution

we have that

(x-275)(0.31)+500(0.65)=(x-275+500)(0.50)

solve for x

0.31x-85.25+325=0.50x+112.50

0.50x-0.31x=239.75-112.50

0.19x=127.25

x=669.7 gallons