what is the equivalent resistance for a parallel circuit with three resistors

 For a parallel resistors connection , the voltage drop across the circuit is same while the current that flow is different ,

The overall current  is the sum of the individual current through the circuit

Therefore  from V=IR

I =V/R

 The effective is given by V/R_EFF =V/R+V/R₂+V/R₃

V/R_EFF =V(1/R+1/R₂+1/R₃)

1/R_EFF =(1/R+1/R₂+1/R₃)
the equivalent resistance is the sum of the reciprocal of the  individual resistance