The monthly rent of a shop was raised by 15%, and six months later by a further 10%, reaching ₹30,360. What was the rent before the first rise?

If the original rent was $R$, then $Rx1.15\times 1.10=30360$. Since $1.15\times 1.10=1.265,R=30360/1.265$ = ₹24,000. Check: 24000 -> 27600 -> 30360. ₹24,288 divides by 1.25, treating the two rises as a single 25% - they compound, so the true factor is 26.5%. ₹26,400 and ₹27,600 undo only one of the two rises.