9000139301
Level:
A
Five different pieces of fruit are there on the plate. In how many ways it is possible
to distribute them into five children, if each child should have one piece?
\(120\)
\(100\)
\(140\)
\(160\)
Combinatorics
9000139706
Level:
A
The international alphabet contains \(26\)
letters. The letters of this alphabet and the digits from
\(0\) to
\(9\) are used to form a
code of the length \(4\)
(a code contains \(4\)
characters). The characters may repeat through the code and the code is not case
sensitive (uppercase letters are equivalent to lowercase letters). How many codes can
be obtained?
\(36^{4}=1\:679\:616\)
\(10\cdot 26^{4}=4\:569\:760\)
\(\frac{36!}
{32!\, 4!}=58\:905\)
\(\frac{26!}
{22!\, 4!}=14\:950\)
9000139302
Level:
A
The phone number contains nine digits. A witness does not remember
the full number, but he remembers that the phone number starts by
\(728\), ends
by \(01\)
and there is no repeating digit in the number. How many phone numbers meet these
conditions?
\(120\)
\(320\)
\(520\)
\(720\)
9000139709
Level:
A
Find the number of possible ways how to organize a group of
\(10\)
children in one ordered row if Mike and Paul should be next to each other.
\(2\cdot 9!=725\:760\)
\(10!=3\:628\:800\)
\(\frac{10!}
{2!} =1\:814\:400\)
\(\frac{10!}
{8!} =90\)
9000139308
Level:
A
The shooting club has \(25\)
members. Among the members it is necessary to vote a board: a president, a cashier
and a webmaster. One person cannot have more than one of these positions and there
is only one member skilled enough to be a webmaster. How many possibilities exist to
set up the board?
\(24\cdot 23=552\)
\(25\cdot 24=600\)
\(24\cdot 23\cdot 22=12\:144\)
\(25\cdot 24\cdot 23=13\:800\)
9000140505
Level:
B
Simplify \(\frac{72!}
{70!+71!}\).
\(71\)
\(72\)
\(\frac{72}
{141}\)
\(\frac{72!}
{141!}\)
9000140509
Level:
B
Find the solution set of the equation assuming
\(x\in \mathbb{N}\).
\[
(x + 1)! = 6(x - 1)!
\]
\(\{2\}\)
\(\{ - 3;\ 2\}\)
\(\left \{\frac{5}
{7}\right \}\)
\(\left \{\frac{7}
{5}\right \}\)
9000139306
Level:
A
How many different ice cream bowls can be prepared from
\(8\) kinds
of an ice cream if the bowl contains just three different kinds of ice cream?
\(\frac{8!}
{3!\; 5!}=56\)
\(\frac{8!}
{2!\; 5!}=168\)
\(\frac{8!}
{5!}=336\)
\(8!=40\:320\)
9000140510
Level:
B
Find the solution set of the equation assuming
\(x\in \mathbb{N}\).
\[
(x + 1)! + x! = 6x + 12
\]
\(\{3\}\)
\(\{2\}\)
\(\{1\}\)
\(\{4\}\)
9000139309
Level:
A
There are \(20\) tablets in an
e-shop. From this amount \(18\)
tablets are new and \(2\)
tablets have been returned by customers. The e-shop manager gets an order
containing three tablets and he wants to get rid of the returned tablets first. How
many possibilities exist to complete the order?
\(18\)
\(\frac{18!}
{3!\; 15!}=816\)
\(18\cdot 16\cdot 3=864\)
\(20\cdot 19\cdot 18=6\:840\)