Answer:
The manager's estimate was really accurate. The correct income was of 6408 $ instead of the 6400$ he estimated.
Explanation:
There are 37 x 23 = 851 seats. 200 of them are occupied by children, 651 are occupied by adults.
200 x 6 = 1200 $ are raised with child tickets,
651 x 8 = 5208 $ are raised with adult tickets.
The total income is 1200 + 5208 = 6408 $, so the manager's estimate was really accurate.