Here are the masses, in grams, of 23 pencils.

[tex]\[
\begin{tabular}{|c|c|}
\hline Mass & Frequency \\
\hline 3 & \bigcirc \bigcirc \\
\hline 4 & \bigcirc \bigcirc \bigcirc \bigcirc \bigcirc \\
\hline 5 & \bigcirc \bigcirc \bigcirc \\
\hline 6 & \bigcirc \bigcirc \bigcirc \bigcirc \\
\hline 7 & \bigcirc \\
\hline
\end{tabular}
\][/tex]

Key: [tex]$\bigcirc = 2$[/tex]

Find how many more pencils had a mass of 4 grams than 7 grams.



Answer :

To solve this problem, we'll use the provided information on the key to determine the number of pencils for each mass.

1. Understand the Key:
The key indicates that one circle ([tex]\(\bigcirc\)[/tex]) represents 2 pencils.

2. Determine the frequency for each mass using the key:

- The frequency for the mass of 4 grams is represented by 2 circles.
[tex]\[ \text{Frequency for 4 grams} = 2 \times 2 = 4 \text{ pencils} \][/tex]

- The frequency for the mass of 7 grams is represented by 0 circles.
[tex]\[ \text{Frequency for 7 grams} = 0 \times 2 = 0 \text{ pencils} \][/tex]

3. Calculate the difference:
To find how many more pencils had a mass of 4 grams than 7 grams, we subtract the frequency for the 7 grams mass from the frequency for the 4 grams mass.
[tex]\[ \text{Difference} = 4 \text{ pencils} - 0 \text{ pencils} = 4 \text{ pencils} \][/tex]

Thus, there are 4 more pencils with a mass of 4 grams than with a mass of 7 grams.