C = 8/7(k - 55)
7/8 c = k - 55
k = 7/8 c + 55
-8 + -7 + -5 + -3 + 3 + 5 + 7 + 8
_______________________
8
0
___
8
your answer is 0!
Set up a proportion.

Cross multiply:

Divide 20 to both sides:

So it will take 62.5 minutes for her to complete the worksheet.