Hypothesis testing — practice question

Harry has a spinner with five sectors, coloured blue, green, red, yellow and black. Harry suspects that the spinner could be biased. He intends to carry out a hypothesis test with the following hypotheses: $H_0:\;P(\text{the spinner lands on blue}) = \frac{1}{5}$ and $H_1:\;P(\text{the spinner lands on blue}) \neq \frac{1}{5}$. Harry spins the spinner 300 times, and blue comes up on 45 of the spins.