Karen is a dog groomer. Rottweilers take 20 minutes to groom, border collies take 10 minutes to groom, and chihuahuas take 45 minutes to groom because they ferociously resist. How many minutes will it take Karen to groom 6 Rottweilers, 9 border collies and 1 chihuahua?
First find the total time Karen spending grooming Rottweilers: 20 minutes/Rottweiler * 6 Rottweilers = <<20*6=120>>120 minutes
Then find the total time she spends grooming border collies: 10 minutes/border collie * 9 border collies = <<10*9=90>>90 minutes
Then add the time spent grooming all three kinds of dogs to find her total grooming time: 120 minutes + 90 minutes + 45 minutes = <<120+90+45=255>>255 minutes
#### 255