Answer:
100 customers
Step-by-step explanation:
Note that when you say "The probability that a customer receives a $25 gift card is 19", I assume you mean 1/9, not 19 because probability cannot exceed 1.
There are 900 reward cards in total, which means 900 customers have a chance to receive a reward. Out of these 900 customers, 1/9 of them receive a $25 gift card, so in order to find how many receive a gift card, we do:
(1/9) * 900 = 100
Thus, 100 customers receive a $25 gift card.
