Final answer:
To determine how many granola bars Simon bought, multiply the number of boxes 'b' by 19, resulting in the expression 19b.
Step-by-step explanation:
Simon bought b boxes of granola bars, and there are 19 granola bars in each box. To find the total number of granola bars Simon bought, we need to multiply the number of boxes by the number of granola bars per box. The expression that shows how many granola bars Simon bought is:
19b
Where b represents the number of boxes of granola bars Simon bought, and 19 represents the number of granola bars in each box. Therefore, if Simon bought 5 boxes, for example, he would have 19 × 5 = 95 granola bars in total.