Arithmetic series/sequence simple problem
I have to use term or sum arithmetic series/sequence formulas to solve the 3 parts of this problem, but I don't understand how to convert the numbers provided into a usable equation.
An airline is marketing a flight to a tourist destination. In the first week of the marketing campaign the ticket sales increase from the usual 85 tickets sold to 124 tickets sold. This means that in the first week there is an increase in ticket sales of 39. In the second week sales increase by 32. In the third week sales increase by 25. The increase in ticket sales continues to reduce by 7 each week of the campaign. The campaign lasts for 5 weeks.
1. Write down the increases in ticket sales for the 5 weeks of the campaign.
2. Find the number of tickets sold each week for the 5 weeks of the campaign.
3. Find the total number of tickets sold over the 5 weeks.