Cleaning solution was made by mixing 10 qt. of a 4% baking soda solution and 8 qt. of a 45% soap solution. Find the concentration of the cleaning solution.

(10 qt)(4%) +(8qt)(45%)=(18 qt) (x)

where x=final concentration of the cleaning solution

(10 qt)(4%) +(8qt)(45%)=(18 qt) (x)

(10 qt%) +(360qt%)=(18 qt) (x)

(370qt%)=(18 qt) (x)

(370qt%)/18qt=(18 qt) (x)/18 qt

21%=x