In data interpretation, a graph shows a steady increase from 10 to 70 over 6 intervals. What is the average rate of increase per interval?

• A. 60 per interval
• B. 6 per interval
• C. 12 per interval
• D. 10 per interval

Answer: (D)

Average rate of increase is the total change divided by the number of intervals. The value rises from 10 to 70, a total change of 60. With 6 intervals, 60 divided by 6 gives 10. So the average increase per interval is 10 units. Since the rise is steady, each interval adds 10 units. The other options would imply different total changes per interval that don’t match the 60-unit gain over 6 intervals.