Solve mixture problem

Question

how many gallons each of 20% alcohol and 10% alcohol should be mixed to obtain 10 gal of 11% alcohol

Answer 1

This is a simultaneous equation problem.

 

Let x = the number of gallons of 20%; let y = the number of gallons of 10%.

 

So, x + y = 10

 

Second equation: 20x + 10y = 10 times 11

 

To finish, express x in terms of y: x = 10 - y, then substitute this expression for x into the second equation and solve for the value of y.

 

Use first equation to solve for x.