I have some difficulties with mixture word problems. In one of the problems in the book the question was the following:
A health clinic uses a solution of bleach to sterilize petri dishes in which cultures are grown. The sterilization tank holds 100 gal. of a solution of 2% ordinary household bleach mixed with pure distilled water.. New research indicates that the concentration of bleach should be 5% for complete sterilization. How much of the solution should be drained and replaced with bleach to increase the bleach content to the recommended level?
So what I did was this, I set up the following equation:
100(.02) - (.02x) + (x) = 100(0.05)
I then solved for x and got the correct answer. Now another question asks this question:
The radiator in a car is filled with a solution of 60% antifreeze and 40% water.The manufacturer of the antifreeze suggests that, for summer driving, optimal cooling of the engine is obtained with only 50% antifreeze. If the capacity of the radiator is 3.6 L how much coolant should be drained and replaced with water to reduce the antifreeze concentration to the recommended level?
So I set up my equation like the one above and got this:
3.6(.6) - (.06x) + (x) = 3.6(.5)
In the end once I solved for x, the answer I got was a negative and wrong. Can someone please explain to me where I keep going wrong? Thanks