The resistance 2 Ω, 4 Ω and 8 Ω are connected in parallel. Their equivalent
resistance is
a) 10 Ω
b) 8/7 Ω
c) 7.5 Ω
d) 14 Ω

The answer to your question is the letter B. R = 8/7 Ω

Explanation:

Data

R1 = 2 Ω

R2 = 4Ω

R3 = 8Ω

To calculate the total resistance use the formula

         1/R = 1/R1 + 1/R2 + 1/R3

-Substitution

         1/R = 1/2 + 1/4 + 1/8

- Look for the Greatest common factor

              2   4   8    2

               1   2    4   2

                    1    2   2

                          1

The GCF = 2 x 2 x 2 = 8

-Sum up the fractions

                 1/2 + 1/4 + 1/8 = (4 + 2 + 1) / 8

                                        = 7/8

-Find R

               1/R = 7/8    then, R = 8/7 Ω