Ralph has two accounts with South Trust National Bank. Over the summer, he mows lawns and deposits his earnings weekly into his savings account. Ralph also eats out every day and
uses the money in his checking account to pay for his meals. Besides these two transactions,
he does not deposit or withdraw funds from either of these accounts.
The amount in his savings account over time is represented in the table below. He spends
$50 on food each week, and after three weeks, he has $1,600 in his checking account.