The total maintenance costs and the machine hours for the past ten accounting periods were as follows:

Period	Machine hours	Maintenance cost
1	400	960
2	240	880
3	80	480
4	400	1200
5	320	800
6	240	640
7	160	560
8	480	1200
9	320	880
10	160	440

Predict the maintenance cost for a machine that has worked for 300 hours.