please work out chi squared, p value and also what is the null hypothesis?

Question

Tom keeps a jar with coins in his office. After a long meeting with Toni discussing statistics, Tom noticed that some coins were missing. Rightfully, Tom accused Toni of ‘borrowing without consent’ some coins, and asked him to empty his pockets. Toni had indeed some coins, but he claimed it was his money. To settle the dispute, you will compare the number of different coins that Toni has in his pocket, and compare them with the expected number if they had come from Tom’s money jar.
The proportion of coins in Tom’s jar was: Half of 10p, one quarter of 20p, and one quarter of 50p.
The number of coins in Toni’s pocket were: 28 of 10p, 24 of 20p, and 56 of 50p.
Perform a Chi-squared test in Excel and answer the following questions.

Answer 1