Sergei has a credit card that uses the average daily balance method. for the
first 12 days of one of his billing cycles, his balance was $350, and for the last
18 days of the billing cycle, his balance was $520. if his credit card's apr is
14%, which of these expressions could be used to calculate the amount
sergei was charged in interest for the billing cycle?

The amount Sergei was charged in interest for the billing cycle is given by, $ 5.2 .

Step-by-step explanation:

According to the question, the amount Sergei was charged in interest for the billing cycle is given by, the sum of the interest on $ 350 for 12 days and the interest on $ 520 for 18 days both calculated at 14% APR.

So, the amount Sergei was charged in interest for the billing cycle is given by,

$ ( +

 $ 5.2

do you mean add both of the equations together

because if you do the answer is 10x-5

step-by-step explanation: