Answer:
She needs 3 purple rectangles.
Explanation:
If Olivia is making 3 scarves and each scarf will be a combination of 3 rectangles, out of the three rectangles, there will be purple meaning a scarf will have at least a purple rectangle.
If a scarf has a purple rectangle then 3 scarves will have;
1 x 3 = 3
3 rectangles.