It’s shown in the picture !!!!!!
Answer: 554
Step-by-step explanation:
If prior population proportion is known, then the formula to find the sample size is given by :-

As per given description, we have
p= 0.1
E=0.025
Critical z-value for 95% confidence : 
Then,

Hence, the minimum sample size required = 554.
So, the fraction of races that he won was:

: you need ti divide the number of occurrences by the number of possibilities.
We can simplify this:

.
When we write it in decimals until the closest place, it's:
0.167 or 16.667%