201902190326 Electric circuit diagrams (Elementary) Q7

The blogger claims no originality of his problem below.

Circuit0006

Find the equivalent resistance of the circuit above.

Solution.

We draw the diagram below:

Circuit0006Sol001

For two resistors $R$ in parallel:

$R_{\mathrm{eq}}=\displaystyle{\frac{R}{2}}$ .

For three resistors $R$ in parallel:

$R_{\mathrm{eq}}=\displaystyle{\frac{R}{3}}$ .

Summing over them in series:

$R_{\mathrm{eq}}=\displaystyle{\frac{R}{2}+\frac{R}{3}+\frac{R}{2}}=\displaystyle{\frac{4}{3}R}$ .