the use of electricity in the US in 1902 was 6.03x10^9 kilowatt-hours
the use of electricity in the US in 1950 was 4.3x10^11 kilowatt hours.
what was the total kilowatt hours of electricity used during these two years
Total kilowatt hours of electricity used during these two years was:
6.03x10^9 + 4.3x10^11 = 4.36x10^11 kilowatt hours.