we have
\(8\frac{39}{40}\)
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
\(8\frac{39}{40}=8+\frac{39}{40}\)
Convert the fraction in a decimal number
\(\frac{39}{40}=0.975\)
Sum the whole number and the decimal number
\(8+0.975=8.975\)
therefore
the answer is
\(8.975\)