we have
[tex]8\frac{39}{40}[/tex]
we know that
In this problem we have a mixed number
A mixed number is a number expressed as the sum of a whole number and a fraction
so
[tex]8\frac{39}{40}=8+\frac{39}{40}[/tex]
Convert the fraction in a decimal number
[tex]\frac{39}{40}=0.975[/tex]
Sum the whole number and the decimal number
[tex]8+0.975=8.975[/tex]
therefore
the answer is
[tex]8.975[/tex]