OpenStudy (anonymous):

If 10^x equals 0.1 percent of 10^y, where x and y are integers, which of the following must be true? A. y=x+2 B. y=x+3 C. x=y+3 D. y=1,000x E. x=1,000y

3 years ago
OpenStudy (kropot72):

The given relationship between x and y can be expressed as $\large 10^{x}=\frac{10^{y}}{1000}\ .........(1)$ Does that make sense as a first step towards a solution?

3 years ago
OpenStudy (anonymous):

hmmmm.... why?

3 years ago
OpenStudy (anonymous):

wait nvm i get it

3 years ago
OpenStudy (anonymous):

3 years ago
OpenStudy (anonymous):

wait why is the 1 at the end? what is that?

3 years ago
OpenStudy (kropot72):

To find 0.1% of a quantity, we divide the quantity by 1000. The (1) at the end is simply a reference number for this equation. We need to use equation (1) to form another equation.

3 years ago
OpenStudy (anonymous):

okay

3 years ago
OpenStudy (kropot72):

Next step is to take logs of both sides of equation (1). Please do that and post your result.

3 years ago
OpenStudy (anonymous):

Hey we don't use logs for this question

3 years ago
OpenStudy (kropot72):

Who says we don't use logs?

3 years ago
OpenStudy (anonymous):

The GRE book I'm using ... There isn't any logs at all

3 years ago
OpenStudy (kropot72):

Does the book suggest a method of solving that doesn't use logs?

3 years ago
OpenStudy (anonymous):

well the solutio|dw:1436987482723:dw|n is this but i don't understand it....

3 years ago