Let’s go through each part of the problem step-by-step.

Given Data:

Solutions:

a. What is the total change in gas price over 5 months?

To find the total change, we add up all the price changes:

$1.20 + (-0.08) + 0.74 + 1.43 + (-2.11) = 1.18$

Total Change: +1.18

b. What is the difference between the September and January price?

This asks for the change from September to January. We take the January value and subtract the September value:

$-2.11 - 1.20 = -3.31$

Difference between September and January: -3.31

c. What is the difference between the October and January price?

This time, we find the difference between the January and October values:

$-2.11 - (-0.08) = -2.11 + 0.08 = -2.03$

Difference between October and January: -2.03

Summary of Answers:

• a. Total change over 5 months: +1.18
• b. Difference between September and January: -3.31
• c. Difference between October and January: -2.03

Would you like further details on any of these solutions, or have any questions?

Here are five related questions you might explore:

1. What would the total price change be if January's price change was +2.11 instead of -2.11?
2. How would the total change differ if each price change was doubled?
3. What is the average monthly change over these five months?
4. If February’s price change was -0.5, what would the new total change be over six months?
5. What is the percentage decrease from the September price change to the January price change?

Tip: When calculating changes over a series, always pay attention to positive and negative signs, as they indicate increases or decreases.