Sequence and Series: JEE Main 2024 Mathematics question

Let $a, a r, a r^2$, ............ be an infinite G.P. If \sum_\limits{n=0}^{\infty} a r^n=57 and \sum_\limits{n=0}^{\infty} a^3 r^{3 n}=9747, then $a+18 r$ is equal to