<ol>

<li>If the magnitudes of vectors a and b are 5 and 12, then the magnitude of vector (b-a) could NOT be</li>

</ol>

<p>Ans: 5. </p>

<ol>

<li>If n distinct planes intersect in a line, and another line l intersects one of these planes in a single pint, what is the least number of these n planes that l could intersect?</li>

</ol>

<p>Ans: n-1</p>

<ol>

<li>In how many ways can 10 people be divided into two groups, one with 7 people and the other with 3?</li>

</ol>

<p>Ans: 120.</p>