Answer:
x +13.
where
x is number of people
Explanation:
Let the number of people be x
given that number of people increased by 13
increased by 13 means that we whatever is the initial number of people, new number of people is 13 more than that.
thus, new number of people = x +13
to translate the number of people increased by 13 into an algebraic expression
we add 13 to number of people which can be represented by x +13.