Answer:
width = 30 units .
Explanation:
Given : perimeter of 90 and a length of 15.
To find : Find the width of a rectangle.
Solution : We have given
Perimeter = 90
Length = 15.
Perimeter of rectangle = 2 ( length+ width).
Plugging the values
90 = 2 (15+ width).
On dividing both sides by 2
45 = 15 + width
On subtracting both sides by 15
45 - 15 = width.
30 units = width.
Therefore, width = 30 units .