bac-s-maths 2023 Q4

bac-s-maths · France · bac-spe-maths__asie_j2 Conditional Probability Combinatorial Conditional Probability (Counting-Based)
For each of the five questions in this exercise, only one of the four proposed answers is correct. No justification is required. A wrong answer, a multiple answer or the absence of an answer to a question neither awards nor deducts points.
We consider L a list of numbers consisting of consecutive terms of an arithmetic sequence with first term 7 and common difference 3, the last number in the list is 2023, namely: $$\mathrm{L} = [7, 10, \ldots, 2023].$$
Question 1: The number of terms in this list is:
Answer AAnswer BAnswer CAnswer D
20236736722016

Question 2: We choose a number at random from this list. The probability of drawing an even number is:
Answer AAnswer BAnswer CAnswer D
$\frac{1}{2}$$\frac{34}{673}$$\frac{336}{673}$$\frac{337}{673}$

We choose a number at random from this list. We are interested in the following events:
  • Event $A$: ``obtain a multiple of 4''
  • Event $B$: ``obtain a number whose units digit is 6''
We are given $p(A \cap B) = \frac{34}{673}$.
Question 3: The probability of obtaining a multiple of 4 having 6 as the units digit is:
Answer AAnswer BAnswer CAnswer D
$\frac{168}{673} \times \frac{34}{673}$$\frac{34}{673}$$\frac{17}{84}$$\frac{168}{34}$

Question 4: $P_B(A)$ is equal to:
Answer AAnswer BAnswer CAnswer D
$\frac{36}{168}$$\frac{1}{2}$$\frac{33}{168}$$\frac{34}{67}$

Question 5: We choose, at random, successively, 10 elements from this list. An element can be chosen multiple times. The probability that none of these 10 numbers is a multiple of 4 is:
\begin{tabular}{ c } Answer A
$\left(\frac{505}{673}\right)^{10}$
&
Answer B
$1 - \left(\frac{505}{673}\right)^{10}$
&
Answer C
$\left(\frac{168}{673}\right)^{10}$
&
Answer D
$1 - \left(\frac{168}{673}\right)^{10}$
\hline \end{tabular}
For each of the five questions in this exercise, only one of the four proposed answers is correct. No justification is required. A wrong answer, a multiple answer or the absence of an answer to a question neither awards nor deducts points.

We consider L a list of numbers consisting of consecutive terms of an arithmetic sequence with first term 7 and common difference 3, the last number in the list is 2023, namely:
$$\mathrm{L} = [7, 10, \ldots, 2023].$$

\textbf{Question 1:} The number of terms in this list is:
\begin{center}
\begin{tabular}{ | c | c | c | c | }
\hline
Answer A & Answer B & Answer C & Answer D \\
2023 & 673 & 672 & 2016 \\
\hline
\end{tabular}
\end{center}

\textbf{Question 2:} We choose a number at random from this list. The probability of drawing an even number is:
\begin{center}
\begin{tabular}{ | c | c | c | c | }
\hline
Answer A & Answer B & Answer C & Answer D \\
$\frac{1}{2}$ & $\frac{34}{673}$ & $\frac{336}{673}$ & $\frac{337}{673}$ \\
\hline
\end{tabular}
\end{center}

We choose a number at random from this list. We are interested in the following events:
\begin{itemize}
  \item Event $A$: ``obtain a multiple of 4''
  \item Event $B$: ``obtain a number whose units digit is 6''
\end{itemize}
We are given $p(A \cap B) = \frac{34}{673}$.

\textbf{Question 3:} The probability of obtaining a multiple of 4 having 6 as the units digit is:
\begin{center}
\begin{tabular}{ | c | c | c | c | }
\hline
Answer A & Answer B & Answer C & Answer D \\
$\frac{168}{673} \times \frac{34}{673}$ & $\frac{34}{673}$ & $\frac{17}{84}$ & $\frac{168}{34}$ \\
\hline
\end{tabular}
\end{center}

\textbf{Question 4:} $P_B(A)$ is equal to:
\begin{center}
\begin{tabular}{ | c | c | c | c | }
\hline
Answer A & Answer B & Answer C & Answer D \\
$\frac{36}{168}$ & $\frac{1}{2}$ & $\frac{33}{168}$ & $\frac{34}{67}$ \\
\hline
\end{tabular}
\end{center}

\textbf{Question 5:} We choose, at random, successively, 10 elements from this list. An element can be chosen multiple times. The probability that none of these 10 numbers is a multiple of 4 is:
\begin{center}
\begin{tabular}{ | c | c | c | c | }
\hline
\begin{tabular}{ c }
Answer A \\
$\left(\frac{505}{673}\right)^{10}$ \\
\end{tabular} & \begin{tabular}{ c }
Answer B \\
$1 - \left(\frac{505}{673}\right)^{10}$ \\
\end{tabular} & \begin{tabular}{ c }
Answer C \\
$\left(\frac{168}{673}\right)^{10}$ \\
\end{tabular} & \begin{tabular}{ c }
Answer D \\
$1 - \left(\frac{168}{673}\right)^{10}$ \\
\end{tabular} \\
\hline
\end{tabular}
\end{center}
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