Since the mean of p, q, r, s and t is equal to 10, we have:
[tex]\frac{p+q+r+s+t}{5}=10[/tex]Then, calculating the mean of p+1, q+2, r+3, s+4 and t+5, we have:
[tex]\begin{gathered} \frac{p+1+q+2+r+3+s+4+t+5}{5} \\ =\frac{p+q+r+s+t}{5}+\frac{1+2+3+4+5}{5} \\ =10+\frac{15}{5}=10+3=13 \end{gathered}[/tex]