Question 1182976
The confidence interval will be given by 

{{{mu - t[0.05]*(s/sqrt(n)) <= X-bar <= mu + t[0.95]*(s/sqrt(n))}}}


{{{55.8 - 1.701*(7.9/sqrt(29)) <= X-bar <= 55.8 + 1.701*(7.9/sqrt(29))}}}


{{{53.3 <= X-bar <= 58.3}}}, with the endpoints rounded to 1 d.p.


Note that we used the t-distribution with degree of freedom 29 - 1 = 28, using a 90% confidence level.