What formula is used to find the circumference of a circle

Steve wants to develop a way to find the total cost of any item including sales tax. the sales tax in his city is 6%. his friend jenna writes the expression x + 6x where x is the cost of the item. explain whether her expression is correct based on the situation.

If olu is twice as old as funmi if the sum of their ages is 60 how old is olu

Im literally having a mental breakdown