Answer:

Step-by-step explanation:
Formula of nth term = 
We are given that an is the foot length in inches that corresponds to a shoe size of n.
We are given that A men’s size 9 fits a foot 10.31 inches long
So, n = 9

Substitute the values in the formula :
So, 
---1
We are given that a men’s size 13 fits a foot 11.71 inches long.
So, n = 13

Substitute the values in the formula :
So, 
---2
Subtract 1 form 2




Substitute the value of d in 1
Substitute the value of a and d in formula given above

So, the explicit formula for the arithmetic sequence is 