ANSWERS: 1

In word problems, "of" always means multiply. In this problem, "mixed with" means add. We will let the number of gallons you need be x. How many gallons of a 60% antifreeze solution: 0.6x (because 60% is 0.6, and of means multiply) must be mixed with: + 100 gallons of 25% antifreeze: 25 (this is 100*0.25) to get: = a mixture that is 50% antifreeze: (100+x)(0.5) [This step is because you must multiply the total gallons (100+x) by the percent antifreeze you want (0.5)] Now, put the pieces of your equation together: 0.6x + 25 = (100+x)(0.5) Solve this equation for x, and you will know how many gallons you need.
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