A balloon is filled with helium at a pressure of 2.4 x 105 Pa. The balloon is at a
temperature of 18 oC and has a radius of 0.25 m. (a) How many helium atoms are
contained in the balloon? (b) Suppose we double the number of helium atoms in the
balloons, keeping the pressure and the temperature fixed. By what factor does the radius
of the balloon increase?