You improve your time running a course by 5 seconds in week one, by 3 seconds in week two, and by 4 seconds in week three. What is the mean weekly change in your running time?

Step-by-step explanation:

Average Value

The mean or average of a number n of measurements is defined as the sum of all values divided by n.

The running times in seconds are being improved by the following numbers:

5, 3, 4

This is the dataset where we have to find the mean value. Here n=3. Applying the formula:

b

step-by-step explanation:

a difference is the result of subtraction. while each of these expressions has subtraction in it, a difference will be the result when subtraction is the last operation applied in the order of operations for the expression. this means subtraction must be outside of the parenthesis. only b has this.

tube or goog would be a great resource to with that question