A 9 by 4 centimeter rectangle expands in such a way that the 9–centimeter side is expanding at the rate of 5 centimeters per second and the proportions of the rectangle remain constant. At what rate is the area of the rectangle increasing when its dimensions are 36 by 16 centimeters? A.
120 cm2/s
B.
140 cm2/s
C.
160 cm2/s
D.
180 cm2/s

Ascientist places 24 cells in a petri dish. she knows the cells grow at an exponential rate, doubling in number every hour. how long will it take (in hours) for there to be 1100 cells in the dish? time to 1100 cells: 5.51832530 hours how long will it take to reach 110 cells? time to 110 cells : 2.1963972 hours what is the average rate of change in the number of cells between 9 hours and 11 hours? average rate of change: cells per hour what is the instantaneous rate of change after 7 hours? instantaneous rate of change: cells per hour note: you can earn partial credit on this problem.