The graph below shows the total sales (in thousands of dollars) in a supermarket during a typical 24-hour period. (i) Estimate the rate of sales during the period from 6 A.M. to 12 noon.
(ii) Which 6-hour interval sees the highest rate of sales and what is this rate?
A) (i) $167/hr (ii) 6pm to 12 noon
B) (i) $1167/hr (ii) noon to 6pm
C) (i) $667/hr (ii) 12 noon to 6 pm $1167/hr.
D) none of these

Question

The graph below shows the total sales (in thousands of dollars) in a supermarket during a typical 24-hour period.  (i) Estimate the rate of sales during the period from 6 A.M. to 12 noon. 
(ii) Which 6-hour interval sees the highest rate of sales and what is this rate?
A) (i) $167/hr (ii) 6pm to 12 noon 
B) (i) $1167/hr (ii) noon to 6pm 
C) (i) $667/hr (ii) 12 noon to 6 pm $1167/hr. 
D) none of these

Quizplus · Accepted Answer

(i) From 6 A.M. to 12 noon, the graph shows a rise of approximately $1000, which is over a period of 6 hours. Therefore, the estimated rate of sales during this period is approximately $1000/6 hours = $167/hr.
(ii) The 6-hour interval with the highest rate of sales can be determined by looking at the steepest slope on the graph, which is between 12 noon and 6pm. The rate during this interval can be estimated as the rise in sales ($1500) over the period of 6 hours, which is $1500/6 hours = $250/hr. However, this option is not given in the answer choices. The closest option is (ii) 12 noon to 6pm, but the rate given is incorrect.

The Graph Below Shows the Total Sales (In Thousands of Dollars)