What is the speed of a wave with a wavelength of 3 m and a frequency of .1 hz? a.) 0.03 m/s b.) 0.3 m/s c.) 3.1 m/s d.) 30 m/s

Large helium-filled balloons are used to lift scientific equipment to high altitudes. what is the pressure inside such a balloon if it starts out at sea level with a temperature of 10.0ºc and rises to an altitude where its volume is twenty times the original volume and its temperature is – 50.0ºc ?