posted by Golkhadi nep .
In the summer of 2008 the population of cuckoos in an area was estimated as 560 pairs. If the numbers returning are declining at 4% each year, calculate
(a) the number of pairs of cuckoos in the area in the summer of 2009;
(b) the number of pairs of cuckoos in the area in the summer of 2020
so my guess is that you would start with what ya got
(continue til you get to 2020)
If the population declines at 4%, it means that the surviving population is 96% of the previous year.
In the summer of 2008, there were 560 pairs. So in the summer of 2009, there were 560*(96/100)
= 537.6 pairs (theoretically)
= 538 pairs
In the summer of 2009, the population declined again to 96% of the theoretical population of 2008, thus
=516.1 pairs (theoretically)
= 516 pairs (rounded)