The average newborn weighs 7.5 pounds. About 4.1×10^6 babies are born in the United States every year. What is the approximate total weight in pounds of all the babies born in the U.S. in a year? Write the answer in scientific notation, expressed to the exact decimal place.

Answer 1

To find the approximate total weight of all the babies born in the U.S. in a year, we can multiply the average weight of a newborn by the number of babies born.

The average weight of a newborn is 7.5 pounds, and approximately 4.1 million (or \(4.1 \times 10^6\)) babies are born each year.

We calculate the total weight as follows:

\[ \text{Total weight} = \text{Average weight} \times \text{Number of babies} \]

\[ \text{Total weight} = 7.5 , \text{pounds} \times 4.1 \times 10^6 \]

Now performing the multiplication:

1. First, calculate \(7.5 \times 4.1\): \[ 7.5 \times 4.1 = 30.75 \]

2. Now, include the \(10^6\): \[ 30.75 \times 10^6 \]

The result in scientific notation is:

\[ 3.075 \times 10^7 \]

Thus, the approximate total weight in pounds of all the babies born in the U.S. in a year is:

\[ \boxed{3.075 \times 10^7} \]