MAT-144 · Mathematical Reasoning Topic 04 · Loans
Topic 04 · Review · Q2

Computing the unpaid balance for a credit card statement

Two-part: compute the interest charged on the prior month's unpaid balance, then assemble the new balance from beginning balance, payments, purchases, and that interest.

▸ VIDEO COMING SOON

A short walkthrough explaining what you need to know and how to solve this question type lands here once it's recorded.

ALEKS randomizes the numbers each attempt, but the question shape stays the same. Here are three example versions you might see.

Priya's credit card statement v1

The table below shows a summary of Priya's credit card statement for the month of February.

Transaction typesAmount
Unpaid balance from January (Beginning balance on February 1)$782.50
Payments made during the month of February$90.00
Purchases made during the month of February$245.30

(a) Suppose the credit card company charges 1.5% monthly interest on the unpaid balance from January. How much interest will this be?
(b) What will Priya's unpaid balance be on her March 1 statement? (Assume that this balance will include the interest from part (a), but will not include any interest on her February balance yet.)

Marcus's statement v2

Marcus's credit card statement for July: beginning balance (unpaid from June) $1,124.40, payments $150.00, purchases $320.18, monthly rate 1.4%.

(a) Find the interest charged.
(b) Find Marcus's unpaid balance on August 1.

Lena's statement v3

Lena's credit card statement for September: beginning balance (unpaid from August) $465.00, payments $45.00, purchases $112.50, monthly rate 1.6%.

(a) Find the interest charged.
(b) Find Lena's unpaid balance on October 1.

Heads up: Your ALEKS version will use different numbers. The numbers in the practice below are different too — that way you're exercising the move, not memorizing one answer.
interest = beginning balance × monthly rate
new balance = beginning − payments + purchases + interest
Two formulas, applied in order. The interest gets computed only on the prior balance — new purchases this month don't accrue interest yet.
1

Identify the four numbers from the table.

Beginning balance on Feb 1: $782.50. Payments: $90.00. Purchases: $245.30. Monthly rate: 1.5% = 0.015.

2

Compute the interest charge (part a).

The credit card company charges interest only on the unpaid balance from January — that's $782.50.

interest = 782.50 × 0.015 = $11.74
3

Assemble the March 1 balance (part b).

Start with the beginning balance, subtract payments, add purchases, add the interest you just computed.

new bal = 782.50 − 90.00 + 245.30 + 11.74 = $949.54

Sanity check: even though Priya paid $90, her balance went UP because purchases ($245) plus interest ($12) outweighed the payment.

▸ COMMON SLIPS(1) Charged interest on the new balance. Interest is on the PRIOR balance only. (2) Used 1.5 instead of 0.015. 1.5% means 1.5/100 = 0.015. (3) Subtracted purchases or added payments. Payments DECREASE the balance; purchases INCREASE it.

Try Marcus's July statement. Same shape, different numbers.

1

Compute the interest charge.

Marcus's beginning balance on July 1 is $1,124.40. Monthly rate is 1.4%. What's the interest charged this month?
interest = $
2

Net the payments and purchases.

Marcus paid $150.00 and made $320.18 in purchases this month. What's the net change to his balance from these two items (before adding interest)?
net change = $
3

Assemble the August 1 balance.

From steps 1 and 2: beginning balance $1,124.40, net change +$170.18, interest $15.74. What's Marcus's unpaid balance on August 1?
new balance = $
▸ NICE WORK

You've walked through the whole problem.

That's the move. ALEKS will give you a different version with different numbers — but the steps are the same.

Q1 Q3