Answer:
Yellow = 18 spools of ribbon
Blue = 15 spools of ribbon
Bobby will have 3 more spools of yellow ribbon.
Answer:
The wide of the walkway is 5ft.
Step-by-step explanation:
In first place you have a rectangular garden of 30ft by 40 ft as shown in Figure 1 (Added file).
So, the area of this rectangle is:

Area=1200ft
Now, the new garden has a walkway of uniform width around it, and the area of the new rectangle is one-half the area of the old garden

In order to be a walkway of uniform width it's necessary to substract of each side the same amount, for this case will be 5 ft, as shown in the Figure 2. Now the new rectangule is 20ft by 30ft.

Which is exactly one-half the area of the old garden.
This means the width of the walkway is 5ft.
It’s 1050.672131
Round to how much your teacher prefers and that’s your answer
Pretty sure that it is the first answer, the one with the back point between 6 & 8
Pythagoras:
sqrt( 9^2+12^2) = sqrt( 81+144) = sqrt(225) = 15! Voila :)