The Charlotte Motor Speedway determines their pricing as follows: r(x)=200[(x-90)]+k
Note that x represents the number of minutes on the track and that r(x) represents the total price in dollars.
Cole Trickle and Rowdy Burns are drivers that have rented the track.
- Cole's team spent $1000 for the time that he drove.
- Rowdy's team spent $800 for the 70 minutes that he drove.
If Cole and Rowdy had been able to combine their minute's total, they would have only paid a total of $1400.
What is the range of minutes (x) that Cole could have driven at the racetrack?