Question

There are 5 resistors, R1 = 3 ohm, R2 = 4 ohm, R3 = 5 ohm, R4 = 3 ohm, R5 = 6 ohm. What will be their equivalent resistance when connected in series?

A)1.28 ohm
B)0.048 ohm
C)21 ohm
D)0.78 ohm

There are 5 resistors, R1 = 3 ohm, R2 = 4 ohm, R3 = 5 ohm, R4 = 3 ohm, R5 = 6 ohm. What will be their equivalent resistance when connected in parallel?

A)0.048 ohm
B)1.28 ohm
C)21 ohm
D)0.78 ohm

Answer 1

series: R = R1+R2+...
parallel: 1/R = 1/R1 + 1/R2 + ...

Better review the topic.
Just FYI, the formulas are reversed when dealing with capacitors.