Answer:
a) 95%
b) 68%
Step-by-step explanation:
Here the distribution given to us is:

a) 97.43 can be written as 98.39 - 2\times 0.48 that is 2 standard deviation.
According to empirical rule, 95% of the observations lies within 2 standard deviations of the mean.
Therefore 95% is the correct answer here.
b) 97.91 can be written as: 98.39 - 1*0.53 that is 1 standard deviations less than the mean
Also, 98.87 = 98.39 + 0.48 that is 1 standard deviations above the mean.
According to the empirical rule, 68% of the observations lies within 1 standard deviation of the mean.