A hairdresser combined three bottles of shampoo into one bottle. The first bottle had 4.8 ounces of​ shampoo, the second bottle had 5.4​ ounces, and the third bottle had 6.6 ounces. The hairdresser used
of the shampoo from the new bottle when she washed her hair. How many ounces of shampoo did she​ use? Describe two different ways to solve the problem.