Alex is making a rectangular garden and wants a fence around it. He wants the length of the garden to be 3 feet longer than the width. 150 feet of fence is all he can afford. What is the greatest possible width he can have for his garden?
Since it's rectangular, there is a length and width. Let the width be w, and the length is then w+3. The total length of the fence is the perimeter, so 150 = 2*w + 2*(w+3) = 4w+6. Solving for w, this becomes w=(150-6)/4 = 144/4 = 36 feet.