An apprenticeship prepares you for a career through a structured program of on-the-job learning with classroom instruction, while you work and earn a salary. The programs can last from one to six years and you can choose careers in areas such as telecommunications, health care, computing, business support and the arts. The most common apprenticeships are in construction and manufacturing. If you like to work with your hands and your mind, you might want to consider an apprenticeship after high school. More than 850 occupations can be learned on the job through an apprenticeship.
In recursion method, a method calls itself until a condition becomes true and returned back. In mystery(), at first time, first is 0 and last is 4. Condition is checked and 0!=4 so else part is executed in which again mystery is called with first as 1 and last 4. This will go again and again until first=4.
When first=4 it is also equal to last so if part is executed and alpha[4] is returned which is 9, now it comes alpha[3] +9 which is 8+9 =17 .
It is returning values to its previous calls that is why it will reduce to alpha[0]+alpha[1]+alpha[2]+17 which is nothing but sum of all elements of a alpha
