/sci/ - Science & Math

I'm doing a math problem right now and this shit is taking forever. I've solved 3 of the 4 questions, but the final one has me stumped and the textbook answer for it isn't helping.

Here's some context for the question:

>Jack has $2500 in a daily-interest savings account. Interest is calculated and compounded daily. The account pays an annual interest rate of 0.15%.

>Jack recently purchased a laptop computer with a before-tax price of $1199. Jack paid for the computer with a credit card. Interest is 28.8% per year and is compounded daily on an overdue balance.

The questions that I've solved so far are the following:

>Calculate the interest earned on Jack's money in 1 year

My answer: $3.75

>Calculate the after-tax cost of the computer if PST is 8% and GST is 6%

My answer: $1366.86

>How much interest will be charged to Goh's credit card if the payment is 30 days overdue from the date of sale?

My answer: $32.73

The final question I'm stumped on is the following:

>Explain why Jack should withdraw money from his savings account and pay for the computer on or before the payment due date.

The textbook answer for this question is this:

>Jack is earning about $0.01 on his savings and is paying over $1.00 per day in interest if he does not pay the bill on time. If he were to make minimum payments on his credit card this would result in additional costs of over $300. During this time he will have earned less than $2.00 on the portion of his savings that would have been needed to pay off his credit card balance.

I understand the $0.01 part because 3.75 divided by 365 can be rounded to 0.01. I understand the $1.00 per day because $32.73 being charged over 30 days means little over a dollar for each of those days. I understand the additional costs of over $300 part, because 0.288 * 1199 is 345.312. What I'm not understanding is the $2.00 portion savings part. That shit makes no fucking sense to me.

I need your help bros.