A student is to answer 10 out of 13 questions in an examination such that he must choose at least 4 from the first five questions. The number of choices available to him is

Since the student is to choose at least 4 questions from first five questions.

$\therefore$ Total number of choices ${=}^5{C}_4{\times }^8{C}_6{+}^5{C}_5{\times }^8{C}_5$

                                              $=140+56=196$.