Jack earns $ 100 on the first day, $ 60 on the second day, $ 150 on the third day, $ 80 on the fourth day and $ 90 on the fifth day. What was his average earnings?

Select for each of the following statements whether it is correct or incorrect. (a) in an isothermal expansion of an ideal gas. (b) the temperature remains constant. (b) the pressure remains constant. (c) there is work done by the gas. (d) there is heat added to the gas. (e) the change in internal energy equals zero.