SAT Math Multiple Choice Question 368: Answer and Explanation
A bicyclist is training for the Liège-Bastogne-Liège, one of Europe's oldest road bicycle races. The line graph above shows the number of miles she biked each week for eight weeks. According to the graph, what was the greatest change (in absolute value) in the weekly number of miles she biked between two consecutive weeks?
- A. 7
- B. 8
- C. 9
- D. 10
Correct Answer: D
Category: Problem Solving and Data Analysis / Statistics and Probability
Strategic Advice: The greatest change (in absolute value) in miles ridden per week could be an increase or a decrease. Try organizing the changes in a table (or a simple list).
Getting to the Answer: Make a list to show the changes in miles ridden per week between each pair of consecutive weeks. You don't have to worry about whether the change is positive or negative, so to keep things simple, always subtract the smaller number from the larger number. Save yourself some time by skipping weeks that clearly have smaller changes, such as between weeks 1 and 2 and between weeks 3 and 4.
Weeks 2-3: 72 – 64 = 8
Weeks 4-5: 78 – 70 = 8
Weeks 5-6: 85 – 78 = 7
Weeks 6-7: 85 – 75 = 10
Weeks 7-8: 82 – 75 = 7
Of the differences, the greatest is from week 6 to week 7, which is a change of 10 miles, making (D) correct.