Which of the letters will come next in the following series?
$a, ab, abc, abcd, abcde, abcde, ?$

Fill in the blank space for the given series with the correct alternative.
Which term of the series $5, 8, 11, 14, \ldots$ is $320$ (in $^{th}$)?

Study carefully the following arrangement of letters, digits and symbols to answer these

questions.

$M, 7 ,\&, 8, L ,P ,@ ,Q ,N ,\beta ,T ,Y ,3 ,2 ,= ,E ,\$ ,4 ,9 ,\#, G ,H ,5$

If all the symbols are deleted from the arrangement, which of the following will be fourth to the left of the $17^{th}$ element from the left end ?

Second and third digits of each number given below are interchanged. Then,the $1st$ and the last digits of each new number thus formed are interchanged. Which of the following numbers then will be the highest number among the five?
$273, 372, 438, 184, 526$

Choose the correct alternative to complete the series: $aba...baca....ba....bacaabac....aca$

Fill in the blank space for the given series with the correct alternative.
$1, 6, 13, 22, 33, (...)$