1103085403

Two resistors of unknown resistances $R_1$ and $R_2$, where $R_1<R_2$ are connected in series (Figure A) and total resistance of the circuit is $R_S=64\mathrm{\Omega }$. If the resistors are connected in parallel (Figure B), the total resistance $R_P=15\mathrm{\Omega }$. Find $R_1$.