Solve each problem. 23) The number of pencils sold varies directly as the cost. If 5 pencils cost $0.45, find the cost of 7 pencils. 24) On a scale drawing, 2 feet represents 30 yards. How many yards are represented by 3 feet? 25) On a map, 180 miles are represented by 4 inches. How many miles are represented by 6 inches? 26) The bending of a beam varies directly as its mass. A beam is bent 20mm by a mass of 40 kg. How much will the beam bend with a mass of 100 kg? 27) Y varies directly as the square of x. If y is 25 when x is 3, find y when x is 2. 28) The distance needed to stop a car varies directly as the square of its speed. It requires 120 m to stop a car at 70 km/h. What distance is required to stop a car at 80 km/h?