A and B can complete a task in 1.5 days. However, A had to leave a few days before the task was completed and hence it took 2 days in all to complete the task. If A alone could complete the work in 2.625 days, how many days before the work getting over did A leave?

A + B together can do the work in 1.5 days.

A alone can do the work in 2.625 days.

Let's assume total work is 2625.

Then efficiency of A = 1000

Efficiency of A + B = 1750

Efficiency of B = 750

Now in question it has given that A work for some days, which we assume as Y. B work for 2 days.

So $$Y\times \text {efficiency of A} + 2\times \text {efficiency of B} = 2625$$

$$Y\times 1000 + 2\times 750 = 2625$$

$$Y\times 1000 + 1500 = 2625$$

$$Y\times 1000 = 2625 - 1500$$

$$Y\times 1000 = 1125$$

$$Y = 1.125$$ (A's working days.)

So 2 - 1.125 = 0.875 (A's leaving days before the work completed.)