C

1003020901

Level: 
C
Let there be vectors: \(\vec{a}=(1;3;-1)\), \(\vec{b}=(0;3;1)\), \(\vec{c}=(-1;2;2)\). Find \(\vec{a}\times\vec{b}\) and \(\left(\vec{a}\times\vec{b}\right)\cdot\vec{c}\).
\(\vec{a}\times\vec{b}=(6;-1;3); \left(\vec{a}\times\vec{b}\right)\cdot\vec{c}=-2\)
\(\vec{a}\times\vec{b}=8; \left(\vec{a}\times\vec{b}\right)\cdot\vec{c}=(-8,16,16)\)
\(\vec{a}\times\vec{b}=(-6;1;-3); \left(\vec{a}\times\vec{b}\right)\cdot\vec{c}=2\)
\(\vec{a}\times\vec{b}=\sqrt{46}; \left(\vec{a}\times\vec{b}\right)\cdot\vec{c}=2\)

9000153901

Level: 
C
Find the number of ways how to distribute \(8\) identical balls among \(5\) persons so that each of them gets at least one ball.
\(\left({7\above 0.0pt 3}\right) = 35\)
\(5^{3} = 125\)
\(\left({12\above 0.0pt 5} \right) = 792\)
\(\left({12\above 0.0pt 8} \right) = 495\)