Current Electricity Part 2

According to given circuit diagram When switch is open, then combination R1 and R2 will be in series and also combination R3 and R4 will be in series and these branches will be in parallel.
∴ Equivalent resistance
(R‌eq ‌)=‌

3R⋅3R

3R+3R

=‌

9R2

6R

=‌

3

2

R
When switch is closed, then combination R1 and R3 will be in parallel and also, combination R2 and R4 will be in parallel. After that, both will be in series.
∴ Equivalent resistance,
(R′eq)‌‌=‌

R⋅2R

R+2R

+‌

R⋅2R

R+2R

=‌

2R2

3R

+‌

2R2

3R

‌‌=‌

2R

3

+‌

2R

3

=‌

4R

3

Now, dividing Eq. (i) by Eq. (ii), we get
c‌

R‌eq ‌

R‌eq ‌‌′

=‌

3 R 2

4‌ R 3

=‌

9

8

x=9