A hollow metal sphere has 7cm and 10cm inner and outer

Question

Solve the all parts of given problem:

Problem: A hollow metal sphere has 7cm and 10cm inner and outer radii, respectively. The surface charge density on the inside surface is -150nC/m². The surface charge density on the exterior surface is +150nC/m2.

Part A: What is the strength of the electric field at points 4cm, 8cm and 12cm from the center?

Part B: What is the direction of the electric field at points 4cm, 8cm and 12cm From the center?

Please show all work and steps, I want to really understand where it is all coming from. Thanks!