7. As part of a new training programme, Habib decides to do sit-ups every day.
He plans to do 20 per day in the first week, 22 per day in the second week, 24 per day in the third week and so on, increasing the daily number of sit-ups by two at the start of each week.
- Find the number of sit-ups that Habib will do in the fifth week.
- Show that he will do a total of 1512 sit-ups during the first eight weeks.
In the \(n\)th week of training, the number of sit-ups that Habib does is greater than 300 for the first time.
- Find the value of \(n\).