A credit card company charges a customer 118 interest on a 90 purchase what is the interest rate?

Approximately 31%

Step-by-step explanation:

First, identify what you know:

1) The original purchase price was $90

2) With the credit card fee, the purchase was $118

First, subtract the total amount by the initial purchase charge, to find out how much the credit card fee was!

$118 - $90 = $28

The credit card fee was $28. What percentage of $90 is $28? Simply divide the extra money charged, by the initial value to figure out!

$28/$90 = 0.31 (line over one, to show infinite)

Now, simply move the decimal point over!

0.31 = 31%

The credit card fee was approximately 31% of $90.

a is the right answer