A village water scheme spent 60% of its fund on the storage tank and committed 25% of what was left to fittings. Of the amount still uncommitted, 20% was returned to the district office, which came to ₹27,000. What was the fund?

Work with what SURVIVES each stage: 40% is left after the tank, 75% of that after the fittings, and 20% of the rest goes back. So the returned amount is $0.40\times 0.75\times$ 0.20 = 0.06 of the fund, and the fund is 27,000/0.06 = ₹4,50,000. ₹9,00,000 multiplies the rates as printed $(0.60\times 0.25\times 0.20=0.03)$ instead of the surviving shares. ₹1,35,000 divides by 0.20 alone, stopping at the last stage. ₹3,37,500 divides by $0.40\times 0.20$, skipping the fittings stage.