$(3)$ What is the time complexity of indexing an element in an array with $N$

elements in total?

Answer:

$($A$)O(N)$

$($B$)O(N^2)$

$($C$)O(1)$

$($D$)O(logN)$

$(4)$ What is the value of the postfix expression $"a+\frac{c}{?}"$ when $a$ is $10,b$ is $4,$

and

c is $2?$ Answer:

$($A$)14$

$($B$)7$

$($C$)5$

$($D$)6$

$(5)$ Numbers $16,8,19,1,20$ are sequentially added to a queue $(16$ added

first and $20$ added last$),$ which number comes out of the queue first?

Answer:

$($A$)16$

$($B$)1$

$($C$)8$

$($D$)20$