Hi, I need help with a word problem. I have the equation but have not done algebra in over 20 years. Here's the problem.

Find the amount of aspirin to give a child of age 10 if the usual adult dosage is 325 milligrams.

Equation: M=cx/c+12

Now M=325 and c=10, do I use a 10x as the nominator and 10 +12 as the denominator?