Dosage of Medicine: solving M=cx/c+12 for x

[lskobe02]

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?

[little_dragon]

yeh
then U do 22 for the denom (simplify)
then crossmultiply to get 22*325=10x
then U do 7150 on the left
then div by 10 to get the ans.