Final answer:
Antoine initially spent $12 on grapefruits (4 pounds × $3/pound) but then received $7 from his mother. The change in his amount of money is a decrease of $5 overall.
Step-by-step explanation:
The student is asking to calculate the change in the amount of money Antoine has after he pays for grapefruit and his mother reimburses him for some of it. First, we find out how much Antoine spent on the grapefruit. He bought 4 pounds of grapefruit at $3 per pound. To find the total cost, we multiply the number of pounds by the cost per pound:
4 pounds × $3/pound = $12.
Next, we need to consider the $7 Antoine's mother gave him:
$12 (initial amount spent) - $7 (amount given by his mother) = $5.
So, the change in the amount of money Antoine has is a decrease of $5 overall after these transactions. This is calculated by subtracting the amount given by his mother from the initial cost of the grapefruits.