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:

$$\boxed{{\displaystyle 3.075\times {10}^7}}$$