The time taken, t, for passengers to be checked-in for a flight is inversely proportional to the square of the number of staff, s, working. It takes 30 minutes passengers to be checked-in when 10 staff are working.

Find an equation connecting t and s.​

Asales representative from a local radio station is trying to convince the owner of a small fitness club to advertise on her station. the representative says that if the owner begins advertising on the station today, the club's total number of members will grow exponentially each month. she uses the given expression to model the number of club members, in hundreds, after advertising for t months.