To determine the best scale for the vertical axis of the dual bar chart, we need to consider the highest value in the data table.

Data from the table:

• Theatre: Adult: 10, Child: 26
• Museum: Adult: 4, Child: 13
• Garden: Adult: 13, Child: 8

The highest value in the table is 26 (Child tickets for Theatre). The vertical axis has 14 rows, so we need to find an appropriate value for "A" such that the highest value (26) fits well within the grid of 14 rows.

Step-by-step calculation:

1. The vertical axis needs to represent the maximum value in the data, 26.
2. Since there are 14 rows, we can divide 26 by 14 to get an approximate scale for each row: $\text{Scale per row} = \frac{26}{14} \approx 1.86$
3. To have a clean and rounded scale, we can round the scale to 2 per row.

Thus, each row will represent 2 units, and the vertical axis will go up to 28 (14 rows × 2 = 28). This gives a sufficient range to accommodate the highest value of 26.

Conclusion:

The number that should replace "A" on the vertical axis is 2.

Would you like more details or further clarifications on this?

Here are 5 related questions for further practice:

1. How would the scale change if the highest value in the table was 30 instead of 26?
2. If the vertical axis had only 10 rows, what would be the best scale for the axis?
3. How would you plot the dual bar chart for the given data?
4. If the maximum value in the table increased to 50, what would be the new scale with 14 rows?
5. What would happen to the clarity of the graph if the scale were too small or too large?

Tip: Always try to choose a scale that results in clean, easy-to-read increments while fitting all the data values on the chart.