Answer: a) 8.2 * 10^-8 N or 82 nN and b) is repulsive
Explanation: To solve this problem we have to use the Coulomb force for two point charged, it is given by:
[tex]F=\frac{k*q1*q2}{d^{2}}[/tex]
Replacing the dat we obtain F=82 nN.
The force is repulsive because the points charged have the same sign.