Question

in a small town, 10 residents move to new cities each year for 3 years. the equation below is written to represent the situation: ( - 10)·3 = - 30 which description best explains the meaning of - 30 in the equation? a - 30 residents leave the town. b there are - 30 residents in the town. c the change in the number of residents per year is - 30. d the total change in the number of residents in the town due to people moving away is - 30.

Explanation:

• Option A: Saying “-30 residents leave” is an incorrect way of stating. The negative sign represents a decrease in the total, not a negative number of people leaving.
• Option B: There can't be a negative number of residents in a town.
• Option C: The change per year is -10 (since 10 leave each year), not -30. The -30 is the total change over 3 years.
• Option D: Since 10 residents leave each year for 3 years, the total change (a decrease) in the number of residents is \(10\times3 = 30\) less residents. Representing a decrease as a negative value, the total change is -30.

Answer:

D. The total change in the number of residents in the town due to people moving away is -30.