Answer
0.38 rev/s.
Work Step by Step
There is no net external torque on the diver, so her net angular momentum is conserved.
$$L_{tuck}=L_{straight}$$
$$I_t \omega_t = I_s \omega_s$$
$$\omega_s=\frac{I_t }{I_s}\omega_t $$
$$\omega_s=\frac{1}{3.5}(\frac{2rev}{1.5s})=0.38\frac{rev}{s}$$
