Three gases (8.00 \rm g of methane, \rm CH_4, 18.0 \rm g of ethane, \rm C_2H_6, and an unknown amount of propane, \rm C_3H_8) were added to the same 10.0-\rm L container. At 23.0 ^\circ\rm C, the total pressure in the container is 4.70 atm. Calculate the partial pressure of each gas in the container.