Answer:
The amount of money in Enid bank account can be written as a linear equation.
Ye = Xe + $4*m
where Ye is the money that Enid has in her account, m is the number of months that have passed since she opened it, and Xe is the initial deposit.
For Jim, the equation is similar:
Yj = Xj + $3*m
where Yj and Xj are similar as above.
Between May 15 and December 31 of the same year, we have 7 months (where i am counting December because the deposit is made in the first day of the month).
Then we have that:
Ye = $72 = Xe + $4*7 = Xe + $28
Xe = $72 - $28 = $44
So in May 15, Enid deposited $44.
For Jim we have:
Yj = $72 = Xj + $3*7 = Xj + $21
Xj = $72 - $21 = $51
So in May 15, Jim deposited $51.
