A piano teacher gives lessons that are each  hour long. How many piano lessons can the teacher fit into a 12-hour work day

The complete statement is that "A piano teacher gives lessons that are each  3/4 hour long"

Solution:
We can solve this problem using the unity rule. That is first find the lessons that can be given in one hour time then multiply them by 12 to find the lessons that can be given in 12 hours time. 

The piano lesson that can be given in 3/4 hour = 1
The piano less than can be given in 1 hour = [tex] \frac{1}{ \frac{3}{4} } = \frac{4}{3} [/tex]

Therefore the piano lessons that can be given in 12 hours = [tex] \frac{4}{3}*12=16 [/tex]

Therefore, the piano teacher can fit 16 piano lessons into a 12-hour work day