About `3.2 x 10^{8}` people live in the United States. About `3.9 x 10^{7}` people live in Canada.

And about `1.1 x 10^{8}` people live in Mexico.

About how many people live in all three countries altogether?

Barney & noblet customers can choose to purchase a membership for $25 per year members receive 10% off all store purchases 1. how much would a member pay per year if he bought $50 worth of items each year? 2. write a slope-intercept equation that expresses how much a member pays per year using x to represent his purchases per year 3. how much would a member have to spend per year to pay off his membership fee?