Type the correct answer in each box. Use numerals instead of words.

A game has a 10-point, a 25-point, and a 50-point scoring region. The probability of landing in each scoring region is shown in the table. If the expected number of points scored per game is 16.5 points, what is the decimal probability of each missing score in the table?

\begin{tabular}{|l|l|}
\hline Score & Probability \\
\hline 10 & 0.65 \\
\hline 25 & \\
\hline 50 & \\
\hline
\end{tabular}



Answer :

To determine the missing probabilities, we must use the information provided and the expected value calculation.

1. Let [tex]\( p_{25} \)[/tex] be the probability of scoring 25 points, and [tex]\( p_{50} \)[/tex] the probability of scoring 50 points.

2. According to the probability rule, the sum of the probabilities for all scoring regions must equal 1:
[tex]\[ 0.65 + p_{25} + p_{50} = 1 \][/tex]
Simplifying this equation, we get:
[tex]\[ p_{25} + p_{50} = 0.35 \][/tex]

3. The expected number of points scored per game is given as 16.5. The expected value formula for discrete random variables is:
[tex]\[ E(X) = (0.65 \times 10) + (p_{25} \times 25) + (p_{50} \times 50) = 16.5 \][/tex]

4. Substituting 0.65 for the probability of scoring 10 points, we have:
[tex]\[ 6.5 + 25p_{25} + 50p_{50} = 16.5 \][/tex]

5. Isolating the terms involving [tex]\( p_{25} \)[/tex] and [tex]\( p_{50} \)[/tex]:
[tex]\[ 25p_{25} + 50p_{50} = 10 \][/tex]

6. From our earlier equation, we know [tex]\( p_{25} + p_{50} = 0.35 \)[/tex]. We solve for [tex]\( p_{25} \)[/tex]:
[tex]\[ p_{25} = 0.35 - p_{50} \][/tex]

7. Substitute [tex]\( p_{25} \)[/tex] in the expected value equation:
[tex]\[ 25(0.35 - p_{50}) + 50p_{50} = 10 \][/tex]
Simplifying:
[tex]\[ 8.75 - 25p_{50} + 50p_{50} = 10 \][/tex]
[tex]\[ 8.75 + 25p_{50} = 10 \][/tex]
[tex]\[ 25p_{50} = 1.25 \][/tex]
[tex]\[ p_{50} = \frac{1.25}{25} = 0.05 \][/tex]

8. With [tex]\( p_{50} \)[/tex] found, substitute it back to find [tex]\( p_{25} \)[/tex]:
[tex]\[ p_{25} = 0.35 - 0.05 = 0.30 \][/tex]

So, the probabilities are:
[tex]\[ \begin{aligned} & p_{25} = 0.3 \\ & p_{50} = 0.05 \end{aligned} \][/tex]

Thus, the completed table of probabilities would be:
\begin{tabular}{|l|l|}
\hline
Score & Probability \\
\hline
10 & 0.65 \\
\hline
25 & 0.30 \\
\hline
50 & 0.05 \\
\hline
\end{tabular}

Other Questions