Answer: 15
Step-by-step explanation: Perimeter is adding the width and the length together. For a rectangle, it has four sides, so it has two lengths and two widths. The width is 10, so you add 10 + 10 which is 20. The length of the rectangle would be 15 since 15 + 15 is 30, and then 30 + 20 = 50, the perimeter.
