SOLUTION: A radiator contains 15 gal of a 20% antifreeze solution. How many gallons must be drained from the radiator and replaced by pure antifreeze so that the radiator will contain 15 gal

Algebra.Com
Question 190158: A radiator contains 15 gal of a 20% antifreeze solution. How many gallons must be drained from the radiator and replaced by pure antifreeze so that the radiator will contain 15 gal of a 40% antifreeze solution?
You can put solution on your website.
Thanks.

Answer by ankor@dixie-net.com(22740)   (Show Source): You can put this solution on YOUR website!
A radiator contains 15 gal of a 20% antifreeze solution. How many gallons must
be drained from the radiator and replaced by pure antifreeze so that the
radiator will contain 15 gal of a 40% antifreeze solution?
:
Let x = amt of 20% to be drained, and amt of pure antifreeze to be added
:
Pure antifreeze = 1.0x
:
.20(15-x) + 1.0x = .40(15)
:
3 - .2x + 1x = 6
:
-.2x + 1x = 6 - 3
:
.8x = 3
x =
x = 3.75 gal removed and 3.75 gal of pure antifreeze added.
:
:
See if that's true:
.2(15-3.75) + 3.75 = .4(15)
3 - .75 + 3.75 = 6

RELATED QUESTIONS

A radiator contains 15 gal of a 20% antifreeze solution. How many gallons must be drained (answered by ptaylor,checkley77)
A radiator contains 15 gal of 40% antifreeze solution. How many gallons must be drained... (answered by josgarithmetic)
A radiator contains 10 gal of a 20% antifreeze solution. How many gallons must be drained (answered by josgarithmetic)
the radiator of an automobile has a capacity of 16 quarts. it is presently filled with a... (answered by josgarithmetic)
the radiator of an car has a capacity of 16 quarts. it is presently filled with a 20%... (answered by josgarithmetic)
An automobile radiator contains 16 quarts of a 20% solution of antifreeze. How much of... (answered by ewatrrr)
A car's radiator contains 12L of antifreeze at 25% concentration. How many liters must be (answered by nerdybill)
Otto's car radiator contains 20 quarts of a 25% antifreeze solution. How many quarts of... (answered by josgarithmetic)
A radiator holds 3 gallons and is currently full of 25% antifreeze solution. How much... (answered by josgarithmetic)