We know we want the equivalent series resistance of R1 and R2 to be something between 5k Ω and 10k Ω, so let's arbitrarily choose R1 to be 2.2k Ω.

Write down the equation for voltage dividers:

Plug in our known values, Vout, Vin, and R1:

Solve for R2:

We can check that 2.2k Ω + 3.3k Ω = 5.5k Ω, so we're within our limit.

Therefore, one acceptable answer for this problem is: R1 = 2.2k Ω and R2 = 3.3k Ω.