Use linear interpolation to estimate the time when total production reached 12,000 units.

Table of data 3:10 P.M. 11240 1
??:?? P.M. 12000 p
4:07 P.M. 14371 2


Total production of 12000 units is reached at 3:24 P.M.
Check by minutes per unit
Between 4:07 P.M. and 3:10 P.M. (57 minutes)
units grow by (14371 — 11240) or 3131 units.
Thus, minutes per unit are 57 / 3131 = 0.01820 (min/unit)
12000 is 760 units after 11240
Thus, time to produce 760 units is:
0.01820 (minfunit) * 760 (unit)
= 13.83 (min) =14 min (rounded)
= 14 minutes after 3:10 P.M.
Therefore, 12000 units are reached 3:10 + 14 minutes = 3:24 P.M.