A can complete a work in 12 days, B in 15 days. When A and B worked alternatively, when started byOptions12 1/4days14 1/4days12 3/4days13 1/4days

The problem is asking how long it would take for A and B to complete a task if they worked on it alternately, starting with A.

Step 1: Determine how much work each person can do in a day.

A can complete the work in 12 days, so A can do 1/12 of the work in a day. B can complete the work in 15 days, so B can do 1/15 of the work in a day.

Step 2: Determine how much work is done in two days (one day for A and one day for B).

In two days, A and B together can do 1/12 + 1/15 = 5/60 + 4/60 = 9/60 = 3/20 of the work.

Step 3: Determine how many two-day periods are needed to complete the work.

Since 3/20 of the work is done in two days, it would take 20/3 two-day periods to complete the work. This is approximately 6.67 two-day periods.

Step 4: Calculate the total time taken.

Since each two-day period actually represents two days of work, we multiply the number of two-day periods by 2 to get the total number of days.

6.67 * 2 = 13.33 days

However, since A and B are working alternately and A starts, the last day will be a full day of work for A. Since A can do more work in a day than B, the total time taken will be slightly less than 13.33 days.

So, the closest answer is 13 1/4 days.

The problem seems to be about calculating the time it takes for two people, A and B, to complete a task when they work alternately. However, the question is not clearly stated. Could you please rephrase or provide more details?

The question seems to be asking how long it would take for A and B to complete a task if they worked on it alternately, starting with A. Here's how you can solve it:

1. First, find out how much work A and B can do in a day. A can complete the work in 12 days, so A can do 1/12 of the work in a day. Similarly, B can do 1/15 of the work in a day.

2. Next, find out how much work A and B can do together in two days (since they are working alternately). In two days, A and B can do (1/12 + 1/15) of the work. Simplify the fraction to get 9/60 or 3/20 of the work.

3. To find out how long it would take for A and B to complete the work, divide the total work (1) by the amount of work they can do in two days (3/20). This gives you 20/3 or 6 2/3 sets of two days.

4. Since each set is two days, multiply 6 2/3 by 2 to get 13 1/3 days. However, since A starts the work and they are working alternately, A will work on the 14th day.

5. Therefore, the work will be completed in 14 1/3 days. But since we don't have that option, the closest one is 14 1/4 days.