If A alone can complete a work in 20 days and B alone can complete the same in 30 days following statement(s) is/are correct?

I. Ratio of efficiency of A and B is 3 :2.

II. Working together A and B can complete the same work in 12 days.

Both I and II

A = 20 days, B = 30 days,

⇒ Therefore Part I is true.

⇒ Time taken by A + B to complete the work = \(\frac{60}{3 + 2}\) =  \(\frac{60}{5}\) = 12 days.

Therefore, Part II is also true.

Hence, Both I and II are correct.