Whats 10 plus 3 i really dont get this question

Adam used 1072.4 gallons of water over the course of 7 days. how much water did adam use, on average, each day?

The length of a rectangle (x+5) inches long, and the width is 3 2/5 inches. if the area is 51 square inches, write and solve an equation to find the length of the rectangle.

The soccer team is conducting a fundraiser selling long-sleeved t-shirts for $14 and short-sleeved t-shirts for $10. so far the team has sold less than $200 worth of the two types of t-shirts. which inequality best represents x, the number of long-sleeved t-shirts they have sold, and y, the number of short-sleeved t-shirts they have sold?