Matilda and Lorraine work in the mail room of a large company sorting letters. Matilda has already sorted 50 letters and continues sorting at a rate of 50 letters per hour. Lorraine has already sorted 80 letters and continues sorting at a rate of 40 letters per hour. Which function can Matilda and Lorraine use to determine the total number of letters they have sorted after x hours? How many letters will they have sorted after 6 hours?

A.
The function that describes the total number of letters sorted by Matilda and Lorraine in x hours is given by f(x) = 100x + 120. Thus, they will have sorted 720 letters in 6 hours.
B.
The function that describes the total number of letters sorted by Matilda and Lorraine in x hours is given by f(x) = 90x + 130. Thus, they will have sorted 670 letters in 6 hours.
C.
The function that describes the total number of letters sorted by Matilda and Lorraine in x hours is given by f(x) = 130x + 90. Thus, they will have sorted 870 letters in 6 hours.
D.
The function that describes the total number of letters sorted by Matilda and Lorraine in x hours is given by f(x) = 90x + 30. Thus, they will have sorted 570 letters in 6 hours.