Answer: 7
Explanation:
Scientific notation is a method that is used in very large numbers or when we've very small numbers. The number given will be multiplied by its power of 10. In this case,
2.8 trillion = 2,800,000,000,000
= 2.8 × 10^12
0.4 trillion = 400,000,000,000
= 4 × 10^11
Therefore, the times more electricity was there in 1999 than 1950 will be:
= (2.8 × 10^12) / (4 × × 10^11)
= (2.8/4) / (10^12 - 11)
= 0.7 × 10
= 7 times
There were 7 times more electricity that was there in 1999 than 1950.