BlueBolt Bottlers has a bottle-filling process with a mean value of 64 ounces and a standard deviation

Question:

BlueBolt Bottlers has a bottle-filling process with a mean value of 64 ounces and a standard deviation of 8 ounces. Suppose that the upper and lower tolerance limits are 71 and 57 ounces, respectively. What is the process capability ratio? What would the standard deviation have to be in order for the process to meet the tolerance limits 99.7% of the time?