For n resistors in series, the equivalent resistance is given by the sum of the resistances:
[tex]R_{eq} = R_1 + R_2 + ... + R_n[/tex]
In this problem, we have three resistors, so the equivalent resistance of the load is the sum of the resistances of the three resistors:
[tex]R_{eq}=45 \Omega + 55 \Omega + 35 \Omega =135 \Omega[/tex]
