Hi, to answer this question we have to write an equation for each situation.
John’s situation:
The amount of money that John has (y) is equal to his school account (40) minus the product of the number of days (x) and the amount he spends per day( 3)
y =40-3x
As days pass by, John has less money (negative rate of change)
Judy's situation
The amount of money that Judy has in her savings account (y) is equal to the product of the number of days (x) and the amount he saves per day (20/2)
