There are 60 minutes in an hour so the mixed number can be represented as.
[tex]2 \frac{15}{60} [/tex] hours
but can be simplified to
[tex]2 \frac{1}{4} [/tex] hours
As an improper fraction, you multiply 2 by 60 and add that to the 15/60 giving you
[tex] \frac{135}{60} [/tex] hours
Which can be reduced to
[tex] \frac{9}{4} [/tex] hours
