Justin takes three times as long to do a job as Carl does, suppose t represents the time it takes Carl to do the job. Then 3t represents the time it takes Justin. How long does it take Justin if Carl takes (a) 30 sec? (b) 90 sec? (c) 2 min?

3t =

3 * 30 = 90
3 * 90 = 180

is 90 sec

To find out how long it takes Justin to do the job, you can use the equation 3t, where t represents the time it takes Carl to do the job.

(a) If Carl takes 30 seconds, we substitute t = 30 into the equation:
3t = 3(30) = 90 seconds
Therefore, it takes Justin 90 seconds to do the job if Carl takes 30 seconds.

(b) If Carl takes 90 seconds, we substitute t = 90 into the equation:
3t = 3(90) = 270 seconds
Therefore, it takes Justin 270 seconds to do the job if Carl takes 90 seconds.

(c) If Carl takes 2 minutes, we need to convert the time to seconds before substituting into the equation:
2 minutes = 2 * 60 seconds = 120 seconds
Substituting t = 120 into the equation:
3t = 3(120) = 360 seconds
Therefore, it takes Justin 360 seconds to do the job if Carl takes 2 minutes.