Type I & II erros- plz help

Problem:

John has to decide which of two discrete distributions a random variable X has. The Probability Dist. are given by the following table.

X 1 2 3 4 5 6 7

Po .1 .1 .1 .1 .1 .2 .2

P1 .1 .2 .1 .1 .2 .1 .2

John take a single observation and wishes to test the null hypotheses that Po is valid the alternative hypthesis that P1 is true. He has decided to accept the null hypo if he gets a 5, 6 or 7 and reject it.

a- what is the prob of Type I error?

b- What is the prob of Type II error?