Question Number 12319 by tawa last updated on 19/Apr/17
Answered by chux last updated on 19/Apr/17
$$\frac{\mathrm{R}}{\mathrm{60}}=\frac{\mathrm{20}}{\mathrm{100}−\mathrm{60}} \\ $$$$\mathrm{R}=\frac{\mathrm{20}×\mathrm{60}}{\mathrm{40}}=\mathrm{30}\Omega \\ $$
Commented by tawa last updated on 19/Apr/17
$$\mathrm{God}\:\mathrm{bless}\:\mathrm{you}\:\mathrm{sir}. \\ $$