Two isolated, concentric, conducting spherical shells

Two isolated, concentric, conducting spherical shells have radii R1=0.500m and R2=1.00m, uniform charges q1=+2.00μC and q2=+1.00μC, and negligible thicknesses. What is the magnitude of the electric field E at radial distance

a) r = 4.00 m
b) r = 0.700 m, and
c) r = 0.200 m? With V = 0 at infinity, what is V at
d) r = 4.00 m
e) r = 1.00 m
f) r = 0.700 m
g) r = 0.500 m
h) r = 0.200 m
i) r = 0?
j) Sketch E( r) and V( r).