Science Homework Help

I’m studying and need help with a Physics question to help me learn.

1:  To an order of magnitude, how many piano tuners reside in New York City? The physicist Enrico Fermi  was famous for asking questions like this one on oral  Ph.D. qualifying examinations.

2:  Air is blown into a spherical balloon so that, when its  radius is 6.50 cm, its radius is increasing at the rate  0.900 cm/s. (a) Find the rate at which the volume of  the balloon is increasing. (b) If this volume flow rate  of air entering the balloon is constant, at what rate will  the radius be increasing when the radius is 13.0 cm?  (c) Explain physically why the answer to part (b) is  larger or smaller than 0.9 cm/s, if it is different