1. A rectangular airport runway is x feet long and y feet wide. If its length is to be made 100 feet longer, by how many square feet will its area be increased?
xy + 100y
xy + 100
8. An 8 gram object is attached to a balance beam at a point 22 cm. from the centre of the beam. If the beam is to remain horizontally balanced how many grams must be attached to the other end of the beam 10 cms away from the centre?