Assuming the distribution is continuous, you have
[tex]\mathbb E(X)=\displaystyle\int_1^{29}\frac x{29-1}\,\mathrm dx=\dfrac1{28}\int_1^{29}x\,\mathrm dx=15[/tex]
If instead the distribution is discrete, the value will depend on how the interval of number between 1 and 29 are chosen - are they integers? evenly spaced rationals? etc