The length of a rectangle is increasing at a rate of 1 ft. per second, while the width is increasing at a rate of 2 ft. per second. When the length…

The length of a rectangle is increasing at a rate of 1 ft. per second, while the width is increasing at a rate of 2 ft. per second. When the length is 4 ft. and the width is 5 ft., how fast, in square feet per second, is the area increasing?