We need to count the number of zeros in a number multiplied by a power of 10. Which is shown below:
[tex]40\cdot10^7[/tex]The power of 10 will add a certain number of zeros, which is equal to the expoent of the power, in this case it's 7, but there is one more zero which is present in the "40", therefore the total number of zeros will be 8.
