Answer:
70
Explanation:
We know that the border will be 20 squares twice, and
15 squares twice also what is equivalent to the perimeter, because a quilt has 4 sides, with numbers, it would be the following:
20 * 2 + 15 * 2 = 40 + 30 = 70
So the border will have 70 squares in total. So if the border can have a single design, Lu can use any toy design 70 times if he wants the border to have the same toy design.