9000140505
Level:
B
Simplify \(\frac{72!}
{70!+71!}\).
\(71\)
\(72\)
\(\frac{72}
{141}\)
\(\frac{72!}
{141!}\)
Combinatorics
9000140506
Level:
B
Simplify \(\frac{2!}
{1!} + \frac{3!}
{2!} + \frac{4!}
{3!}\).
\(9\)
\(\frac{29}
{6} \)
\(\frac{9}
{6}\)
\(\frac{12!+9!+8!}
{6!} \)
9000140507
Level:
B
Simplify for \(n\in \mathbb{N}\).
\[
\frac{(n + 2)!}
{n! + (n + 1)!}
\]
\(n + 1\)
\(\frac{n!+2}
{2n!+1}\)
\(\frac{n+2}
{2n+1}\)
\(\frac{n!+2!}
{2n!+1!}\)
9000140508
Level:
B
Simplify for \(n\in \mathbb{N}\).
\[
\frac{(n + 1)!}
{n! - (n + 1)!}
\]
\(- 1 - \frac{1}
{n}\)
\(n + 1\)
\(n! + 1\)
\(- \frac{n+1}
{(n-1)!}\)
9000140509
Level:
B
Find the solution set of the equation assuming
\(x\in \mathbb{N}\).
\[
(x + 1)! = 6(x - 1)!
\]
\(\{2\}\)
\(\{ - 3;\ 2\}\)
\(\left \{\frac{5}
{7}\right \}\)
\(\left \{\frac{7}
{5}\right \}\)
9000140510
Level:
B
Find the solution set of the equation assuming
\(x\in \mathbb{N}\).
\[
(x + 1)! + x! = 6x + 12
\]
\(\{3\}\)
\(\{2\}\)
\(\{1\}\)
\(\{4\}\)
9000141501
Level:
B
Let \(A\) be set with
\(n\) mutually different
elements. If \(n\) is increased
by \(2\), then number
of \(3\)-permutations
is increased by \(384\).
Find \(n\). (The term
„\(k\)-permutation” stands for
an ordered arrangement of \(k\)
objects from a set of \(n\)
objects.)
\(8\)
\(64\)
\(32\)
9000141502
Level:
B
Let \(A\) be set with
\(n\) mutually different elements.
The number of \(5\)-permutations
with repetition is \(1024\).
Find \(n\). (The term
„\(k\)-permutation
with repetition” stands for an ordered arrangement of
\(k\) objects from
a set of \(n\)
objects, when each object can be chosen more than once.)
\(4\)
\(5\)
\(2\)
9000141503
Level:
B
Let \(A\) be a
set with \(n\)
mutually different elements. If two elements are removed from
\(A\), the number of all
permutations of set \(A\)
decreases \(20\)-times.
Find \(n\).
\(5\)
\(4\)
\(5\) or
\(- 4\)
9000141504
Level:
B
Let \(A\) be a
set with \(n\)
mutually different elements. If we add one element to the set
\(A\), the number of
\(3\)-combinations
of a set \(A\) is
increased by \(21\).
Find \(n\).
\(7\)
\(6\)
\(43\)