Is there any picture or something ?
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<span> 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
</span>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
The sequence:
a 1 = 30, a 2 = 70, a 3 = 110, a 4 = 150, a 5 = 190,...
a 2 = a 1 + d
70 = 30 + d
d = 70 - 30 = 40
a n = a 1 + ( n - 1 ) * d
For the 25th month:
a 25 = 30 + 24 * 40 = 30 + 960 = 990
Answer: B ) 990.