A sum of money at compound interest becomes 3 times in 6 years. How many years will it take to become 27 times? MCQ with Answer and Explanation

Explanation:
Original × 0.9 × 0.9 = 162000 → Original = 162000/0.81 = 200000.

Explanation:
0.2 × 500 = 100.

Explanation:
Original x, xy=120. New 0.8x(y+5)=120 → 0.8×120 + 4x =120 → 96+4x=120 → 4x=24 → x=6, reduced 4.8? Wait: original x=6, reduced price = 0.8*6=4.8, option C. Check: original 6 per kg, 20 kg for 120. Reduced 4.8, buys 25 kg for 120, 5 kg more. So reduced price = 4.8. Option C. So answer C.