Answer:
Day 52
Step-by-step explanation:
Let the number of days be d,
pencil left in stock = total pencils - sold pencils per day
solve:
460 = 1500 - 20d
460 - 1500 = -20d
-20d = -1040
d = -1040/-20
d = 52
At day 52, the manager has recorded the pencil left.