Below is an instruction that describes a task. Write a response that appropriately completes the request in Swahili. Please answer in Swahili.

### Instruction:
It takes 10 minutes to wash a car, 15 minutes to change oil, and 30 minutes to change a set of tires.  If mike washes 9 cars, changes the oil on 6 cars, and changes two sets of tires how many hours did he work?

### Response:
 Alitumia dakika 10 * magari 9 = <<10*9=90>>90 kusafisha magari.
Alitumia dakika 15 * magari 6 = <<15*6=90>>90 kubadilisha mafuta.
Alitumia magari 2 * dakika 30 = <<2*30=60>>60 kubadilisha matairi.
Alitumia jumla ya dakika 90 + dakika 90 + dakika 60 = <<90+90+60=240>>240.
Alitumia dakika 240 / dakika 60 = <<240/60=4>>4 saa kwenye kazi hizi.