Respuesta :

the answer is 210.
every year the rate goes down by 50% or half. half of 3360 is 1680 and half of 840 is 420.
The number of births in year 5 would be 210. It is a pattern.
1680 + 1680 is 3360
840 + 840 is 1680
420 + 420 is 840
and 210 + 210 is 420