The diagram shows a 40 Ω resistor and a 60 Ω resistor connected in parallel.
What is the total resistance between points P and Q?

The diagram shows a 40 Ω resistor and a 60 Ω resistor connected in parallel.

Equivalent resistance for the parallel combination of resistance is given by,

${\displaystyle \frac{1}{R_{eq}}}={\displaystyle \frac{1}{R_1}}+{\displaystyle \frac{1}{R_2}}$

Hence,

$R_{eq}={\displaystyle \frac{R_1\times R_2}{R_1+R_2}}$

Given, $R_1=40\mathrm{\Omega }$

          $R_2=60\mathrm{\Omega }$ 

$⟹R_{eq}={\displaystyle \frac{40\times 60}{40+60}}$

$⟹R_{eq}=24\mathrm{\Omega }$

So, it is less than 40 Ω.