SOLUTION: A car radiator is filled with 4 gal of a 30% antifreeze solution. How much pure antifreeze must be added to have a 75% antifreeze solution?

Question 723331: A car radiator is filled with 4 gal of a 30% antifreeze solution. How much pure antifreeze must be added to have a 75% antifreeze solution?
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
A car radiator is filled with 4 gal of a 30% antifreeze solution. How much pure antifreeze must be added to have a 75% antifreeze solution?
-----------------------
Equation:
anti + anti = anti
0.30*4 + 1.00*x = 0.75(4+x)
----
Multiply thru by 100 to get:
-----------------
30*4 + 100x = 75*4 + 75x
--------
25x = 45*4
x = (9/5)4
x = 36/5
---
x = 7 1/5 gallons (amt. of pure antifreeze to add)
----------------
Cheers,
Stan H.
============
RELATED QUESTIONS
A mechanic needs a radiator to have 30% antifreeze solution. The radiator currently is... (answered by josgarithmetic)

A mechanic needs a radiator to have 30% antifreeze solution. The radiator currently is... (answered by josgarithmetic)

the radiator of an car has a capacity of 16 quarts. it is presently filled with a 20%... (answered by josgarithmetic)

a car radiator has a capacity of 16 quarts and is filled with a 25% antifreeze solution.... (answered by stanbon)

A car radiator has a capacity of 16 quarts and is filled with a 25% antifreeze solution. (answered by nerdybill)

Weighted Averages. A car radiator has a capacity of 14 quarts and is filled with a... (answered by nerdybill,ptaylor)

a car radiator has a capacity of 16 quartz and is filled with a 25% antifreeze solution.... (answered by mananth,josgarithmetic,greenestamps)

How much pure antifreeze must be added to 10 gal of 20% antifreeze to make a 50%... (answered by Mathtut)

A mechanic needs a radiator to have 40% antifreeze solutions. the radiator currently is... (answered by addingup)