Question 22

The thief left the orchard with $1$ apple.

$\begin{aligned} &\therefore\ \text{ before meeting the }3\text{rd watchman, he must have had }&(1+2)\times 2&=6 \text{ apples.} \\ &\therefore\ \text{ before meeting the }2\text{nd watchman, he must have had }&(6+2)\times 2&=16 \text{ apples.} \\ &\therefore\ \text{ before meeting the }1\text{st watchman, he must have had }&(16+2)\times 2&=36 \text{ apples.} \end{aligned}$

So, the thief stole $36$ apples originally.