Answer:
9
Explanation:
Range = Highest Value - Lowest Value
Range of the shoe size in Jacob's family=3
Two people in the family wear shoe size 6.
Since Jacob's size is not 6 and it is 3.
Let Jacob's size =x
The shoe sizes are therefore: 6,6,x
Therefore:
x-6=3
x=3+6=
x=9
Jacob's shoe size is 9.