1. ## ebay feedback percentages

Hello
Im new to the forum and would like to know how to calculate the additional number of sales i need to make in order to increase my feed back from 99.8 to 99.9 ?
I cuurently have 887 sales and 2 negatives and the feedback is calculated by
887 / (887+2) = %age feedback.
can anyone help ?

2. 'x' is the number of sales with positive feedback you need.

You have $\frac{887}{887+2}$

You need $\frac{887+x}{887+2+x}\;=\;0.999$

With a little algebra, you could solve that for 'x' and pick the next higher integer. You can't have half a feedback, right.

HOWEVER, it may be MUCH easier to do it this way.

1 - 0.998 = 0.002

You have $\frac{2}{887 + 2}$

You need $\frac{2}{887 + 2 + x}\;=\;0.001$

Either way. Again, watch for that partial feedback. Move up to the nearest integer.