Intersection is both A and B, ie $A\cap B$ so it should be the amount in the overlap, ie 600.
That table is setup like this:
\begin{array}{l c l c l c l } & A_1 & A_2 \\ B_1 & A_1 \cap B_1 & A_2 \cap B_1 & \mbox{total of }B_1 \\ B_2 & A_1 \cap B_1 & A_2 \cap B_2 & \mbox{total of }B_2 \\ & \mbox{total of }A_1 & \mbox{total of }A_2 & \mbox{total of }S \end{array}
Where the set A is split into 2 disjoint parts, wlog B is as well S is the total set (sample space)
What you need is Bayes' Theorem
P(1000 Ohms | Bin 4) for ease of typing O = 1000 Ohms , B = Bin 4
$P\left(O|B\right) = \frac{P\left(B|O\right)P\left(B\right)}{P\left(B|O\right)P\left(O\right) + P\left(B|\bar{O}\right)P\left(\bar{O}\right)}$
$P(not a)= P\left(\bar{a}\right) = 1- P(a)$