A is twice as efficient as B. Working together, they finish a job in 12 days. How many days would A take to finish the job alone?

💡 Solution & Explanation

If B does 1 unit of work per day, A does 2 units, so together they do 3 units per day. The whole job is 3 × 12 = 36 units. A alone takes 36 ÷ 2 = 18 days, and B alone would take 36 days. A, being faster, needs fewer days than B but more than the 12 days they take together.