Two point charges are enclosed by a spherical conducting shell that has an inner and outer radius of 13.0 and 15.2 cm, respectively. One point charge has a charge of q1=8.30 μC, while the second point charge has an unknown charge q2 . The conducting shell is known to have a net electric charge of −2.40 μC, but measurements find that the charge on the outer shell is + 3.70 μC. Determine the charge q2 of the second point charge.