If A is thrice efficient as C who is ½ efficient of B and the difference between time taken by A and C is 8 days then find the time taken by A and B together to complete the work? यदि A, C से तीन गुना कुशल है, जो B का ½ कुशल है और A और C द्वारा लिए गए समय के बीच का अंतर 8 दिन है, तो कार्य को पूरा करने के लिए A और B द्वारा एक साथ लिया गया समय ज्ञात कीजिए?

Let C's efficiency = 1 unit. Then A's efficiency = 3 units (A is thrice as efficient as C). B's efficiency = 2 units (C is half as efficient as B, so B is twice C). Time taken is inversely proportional to efficiency. If C takes t days, A takes t/3 days. Difference: t - t/3 = 2t/3 = 8 days, so t = 12 days. Therefore A takes 12/3 = 4 days alone. B takes 12/2 = 6 days alone. Together their rate = 1/4 + 1/6 = 5/12 work per day. Time together = 1 / (5/12) = 12/5 = 2.4 days. Option B (1.6) and C (1.9) are calculation errors, D (9) ignores efficiency.