Probability of 3rd drawing is red?

[Cylab]

There are 7 balls in box--red and white.
What is probability of p-th drawing is red?
{p=1,...7}

Condition:return of previous drawing and not
returning of previous drawing.

Please help me these two conditions please
Thanks in advance

 

[HallsofIvy]

You are the same person who did the "10 boys and girls in line"?

The same thing happens here- if x of the seven balls is red and the drawing of samples is "with replacement", then the probability any one draw is red is x/7. If the drawing is "without replacement" then the probability depends on the previous history. The "a-priori" probability without that information is still x/7.