is the number supposed to increase every 3 hours? if so do we start at 40 or the 640 ?
is this in a room cause if it is it would need to be a big room or they would start to crush each other
is this outside cause then you have to think some will fly away other will see all the birds and join in looking for food and really just think what they will do to any cars nearby
and what kind of birds? robin, pigeon, duck,
hunters would reduce the number if they were ducks
hawks would scare off most of the other birds
you really need to add more details
Lani had 40 birds at first. Then after 3 hours she had 640 , that is , she had now 640-40 more birds = 600. 600 birds in 3 hours , that is , 600/3 per hour = 200 . So after 20 hours she'll have 200 x 20 birds , = 4000 birds . And as we know she had 40 birds already that is now 4040 birds after 20 hours .
