During one year, about 13 million adults over 18 years old in the U.S. spent a total of about 93 billion hours online at home. On average how many hours per day did each adult spend on line at home? How do you write each number in scientific notation? How do you convert the units to hours per day?
To find the average number of hours per day each adult spent online at home, we can divide the total number of hours spent online by the number of adults.
Average hours per day = Total hours spent online / Number of adults
In this case, the total hours spent online is 93 billion hours, and the number of adults is 13 million.
Average hours per day = 93,000,000,000 hours / 13,000,000 adults
To write these numbers in scientific notation, we express them using powers of 10.
93 billion can be written as 9.3 × 10^10 (move the decimal point one place to the left, and the exponent represents the number of places shifted).
Similarly, 13 million can be written as 1.3 × 10^7.
So the average number of hours per day each adult spent online at home can be calculated as:
Average hours per day = 9.3 × 10^10 hours / 1.3 × 10^7 adults
To convert the units from hours to hours per day, we need to divide the total hours by the number of days in a year. Assuming there are 365 days in a year, we divide by 365:
Average hours per day = (9.3 × 10^10 hours) / (1.3 × 10^7 adults) / (365 days)
Simplifying this expression gives us the answer in scientific notation:
Average hours per day = 2.1 × 10^3 hours/day