Question: Worker efficiency an efficiency study conducted for elektra electronics showed that the number of space com mander walkie-talkies assembled by the average worker t hr after starting work at 8 a.m. Is given by
N(t) = -t3 + 6t2 + 15t (0 ≤ t ≤ 4)
At what time during the morning shift is the average worker performing at peak efficiency?