Answer
9250 stores
Work Step by Step
From the chart, we observe that Mcdonalds has 28 symbols while Walmart only has 9.5. The difference in numbers of symbols is:
$$ =28-9.5 =18.5$$
Since each symbol represents 500 stores, the difference in the number of stores is:
$$ =18.5 \cdot 500= 9250$$