I am struggling with this. For some reason, i got 70?

Five pulse rates are randomly selected from a set of measurements. The five pulse rates have a mean of 70.6 beats per minute. Four of the pulse rates are 53, 61, 72, and 90. a. Find the missing value. b. Suppose that you need to create a list of n values that have a specific known mean. Some of the n values can be freely selected. How many of the n values can be freely assigned before the remaining values are determined? (The result is referred to as the number of degrees of freedom.) a. The missing value is | beats per minute. (Type an integer or a decimal. Do not round.) b. Select the correct choice below and fill in the answer box to complete your choice. (Type an expression using n as the variable.) O A. Of the n values, can be freely selected because the remaining value(s) must be equal to the known mean. O B. Of the n values, can be freely selected because the remaining value(s) can be expressed in terms of the mean, median, and midrange of the assigned values. O C. Of the n values, can be freely selected because the remaining value(s) can be expressed in terms of the assigned values and the known mean