Question

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

Answer 1

`10^x=0.1 \% * 10^y \\ \\ 10^x=(0.1)/(100) * 10^y \\ \\ 10^x=(1)/(1000) * 10^y \\ \\ 10^x=(10^y)/(10^3) \\ \\ 10^x=10^(y-3) \\ \\ \log_(10) 10^x=\log_(10) 10^(y-3) \\ \\ x=y-3 \\ \\ y=x+3`

The answer is B.