Let S be the number of Brand S snowboards sold.
Let B be the number of Brand B snowboards sold.
309S + 489B = 4299
S + B = 11
S = 6 snowboards sold
B = 5 snowboards sold
After every month's withdrawals, 4/5 of the original amount at the start of the month will remain. The amount at the start of every month will change. Thus:
an = 4/5 (an-1) ; where a1 = 500.
(5+22)x(35-27)+6x6
27 (35-27)+6x6
27x8+6x6
27x7+36
216+36
=252
The amount of metal he will need to cover the back of the shelves is 180 inches².
The figure above is like a composite figure. Therefore, lets find the area.
<h3>Area of the composite figure</h3>
The area of the figure is the sum of the whole individual 2 dimensional shapes in the composite figure.
Therefore, two rectangles can be drawn from it.
area of rectangle = lw
where
l = length
w = width
Therefore,
area of rectangle 1 = 9 × 8 = 72 inches²
area of rectangle 2 = 6 × 18 = 108 inches²
Total area = 108 + 72 = 180 inches²
Therefore, the amount of metal he will need to cover the back of the shelves is 180 inches².
learn more on area here: brainly.com/question/25849553