Question 1189920
x = number of gallons of premium antifreeze solution.
y = number of gallons of water.


x + y = 255
.85 * x + 0 * y = .3 * 255
multiply both sides of the first equation by .85 and simplify the second equation to get:
.85 * x + .85 * y = 216.75
.85 * x = 0 * y = 76.5
subtract the second equation from the first to get:
.85 * y = 140.25
solve for y to get:
y = 140.25 / .85 = 165
solve for x to get:
x = 255 - 165 = 90
x + y = 90 + 165 = 255.
this confirms total gallons at 255.
.85 * x + 0 * y = .85 * 90 = 0 * 165 = 76.5 / 255 = .3 = 30% antifreeze.
this confirms total antifreeze solution in the inexpensive mixture = 30%.
your solution is:
90 gallons of premium antifreeze and 165 gallons of water must be mixed to get a solution that is 30% antifreeze.