Question

Given three resistor something of resistance R1=100 ohm, R2=3 ohm, R3=10 ohm. The combination of R1, R2, R3 which are in parallel, is connected in series with R2 the resultant resistance Rf is ?

Answer 1

parallel combination=1/R1+1/R2+1/R3

=1/100+1/3+1/10

=1×3+1×100+1×30÷300

=133/300