L + W = 15, (1) (15 =; L is the length, W is the width) L - W = 3. (2) (according to the condition) Add equations (1) and (2). You will get 2L = 15 + 3 = 18. Hence, L = = 9. It is the length, 9 ft. The width is W = L - 3 = 9 - 3 = 6 ft. Answer. L = 9 ft, W = 6 ft.
Let length be L, and width, W
Then, W = L + 3
2(L + W) = 2(15)
L + W = 15
L + L + 3 = 15 ----- Substituting L + 3 for W
2L = 15 - 3
2L = 12
L, or length =, or
Width: 6 + 3, or