Answer:
a.

Step-by-step explanation:
P = 2(L + W)
P = 28
L = 2W - 1
28 = 2(2W - 1 + W)
28 = 2(3W - 1)
28 = 6W - 2
28 + 2 = 6W
30 = 6W
30/6 = W
5 = W ....width is 5 ft
L = 2W - 1
L = 2(5) - 1
L = 10 - 1
L = 9 <=== length is 9 ft
If you would like to know which one of the options is better to buy, you can calculate this using the following steps:
3 sandwiches ... $4.95
1 sandwich ... $x = ?
______________________
3 * x = 1 * 4.95 /3
x = 4.95 / 3 = $1.65
4 sandwiches ... $6.72
1 sandwich ... $y = ?
______________________
4 * y = 1 * 6.72 /4
y = 6.72 / 4 = $1.68
Result: You should buy sandwiches from the first option ($1.65 < $1.68 per unit).