Question

On April 1, the unpaid balance in an account was $218. A payment of $30 was made on April 11. On April 21, a $40 purchase was made. The finance charge rate was 15% per month of the average daily balance. Find the new balance at the end of April.

Answer 1

Important Details:

On April 1, the unpaid balance was 218.
On April 11, a payment of 30 was made.
On April 21, a 40 purchase was made.

Balances summary
from April 1 to April 10, the unpaid balance was 218.
from April 11 to April 20, the unpaid balance was 218 - 30 = 188 ( As, 30 dollar deposit to the account was made)
from April 21 to April 30, the unpaid balance was 188 + 40 = 228 ( As, 40 dollar purchase was made)

Finding the total daily balance for the month and then dividing by the number of days in the month to compute the financial charge

The total balances were:

April 1 to April 10 is = 10 days X 218 = 2180.
April 11 to April 20 is = 10 days X 188 = 1880.
April 21 to April 30 is = 10 days X 228 = 2280.

The total is 6340, and now dividing it by 30 to get an average daily balance of 211.3333

So, the finance charge would be 0.15 x  211.3333 = 31.7

New Balance at the end of April = 228 + 31.7 = $259.70