One JOB = 1 and 2 hours = 120 min
Tyler Rate per minute: 1/120 (in 1 minute he performes 1/120 of the job)
Dakota Rate per minute: 1/90 (in 1 minute he performes 1/90 of the job)
Tyler's + Dakota's rate per 1 minute = 1/120 + 1/90 = 7/360 (Job/minutes)
7/360 of the job was performed in 1 minute
a complete JOB =1 to be performed in x minutes (Rule of three)
x = 1x1/(7/360) that equals to 360/7 and x (time of both) = 51 min 42
