How many ounces of iodine worth 30 cents an ounce must be mixed with 50 ounces of iodine with 18 cents an ounce so that the mixture can be sold for 20 cents an ounce?

Let x be the ounces of 30 cents worth iodine.
We know that we have 50 ounces of 18 cents worth leonine, so we have (50)(18) = 900 cents of iodine.
Now, we can set up our equation and solve for x to get the ounces that should be mixed:
 





We can conclude that we should mix 10 ounces of 30 cents worth iodine, so we can sell the mixture for 20 cents an ounce.

Well if you have 20 bats you probably want 20 balls? you don’t have enough context to answer the question.