Oscillation Equation Typo in Textbook?

[Calpalned]

Homework Statement

Homework Equations

$r=0.15-0.05cos(\omega t)$ $\omega = \sqrt {\frac{k}{m}}$
$\vec{E}=\frac{Qk}{r^2}$

The Attempt at a Solution

In my end result, I got the same thing as above, but with 10^5 in the numerator. According to the solutions guide, the final answer is a simplification of $\frac{2.7*10^4}{(0.15-0.05cos(13.92t))^2}$ Did I make a mistake or did the textbook? Thank you.

 

[NascentOxygen]

Hi Calpalned. Is this a problem easily solved in your head, or is there some working that you have forgotten to attach?

 

[Calpalned]

I solved it already, It just want to check if it's 10^5 or 10^7