Exponents *HW*

[Redrang604]

I would like an explanation on how to go about solving these two. I am having some trouble.

 

24. In 1975, the U.S. EPA set a standard of 50 ppb of lead in drinking water. In 1991, a new standard was set that safe water contains less than 15 ppb.

a.Write each of these rates as fractions using positive powers of 10

b.Write each rate without fractions, using negative powers of 10

[Dave]

I'll do the first one for you, and then it's up to you

 

50 ppb is, I assume, 50 parts per billion. Now, I'll also assume that your version of billion is the American one, hence 1 billion = 10⁹. So 50ppb = 50/10⁹. You should be able to simplify that down.