No, the sequence is algebraic.
Answer:
3 hours
Step-by-step explanation:
Rodriguez did 1/3 of the job, so the remaining 2/3 of the job will take the assistant 2/3 of the usual time:
(2/3)(4 1/2) = 3 . . . hours
The assistant can complete the job in 3 hours.
So the ratios are 5:5 and 3:5 so the fractions are 5/10 (1/2) for 7th grade and 5/8 for 8th grade