To find the total kilowatt-hours of electricity used during the years 1902 and 1950, you'll need to add the two values together.
Given:
- Electricity used in 1902: \( 6.03 \times 10^9 \) kilowatt-hours
- Electricity used in 1950: \( 4.3 \times 10^{11} \) kilowatt-hours
First, convert \( 6.03 \times 10^9 \) so that it has the same exponent as \( 4.3 \times 10^{11} \):
\[ 6.03 \times 10^9 = 0.0603 \times 10^{11} \]
Now, add the two amounts:
\[ (0.0603 \times 10^{11}) + (4.3 \times 10^{11}) = (0.0603 + 4.3) \times 10^{11} = 4.3603 \times 10^{11} \]
Thus, the correct total kilowatt-hours of electricity used during these two years is:
\[ 4.3603 \times 10^{11} \]
So, the correct response is: \[ (6.03 \times 10^9) + (4.3 \times 10^{11}) = 0.063 \times 10^{11} + (4.3 \times 10^{11}) = 4.3603 \times 10^{11} \]