[填空题]
The Australian Koala Foundation estimates that there asj r+ocf- f,ya -csre rp-km/** us:5ere about ,3*it) c4)yxcjns)37x 4om;jarxhpzr ouv2 o 45000 koalas left in the wild in 2019. A year before, in 2018, the population of koalas px74)toyo2 ro* cc r,) xim)zhvja;j xs3un34was estimated as 50000. Assuming the population of koalas continues to decrease by the same percentage each year, find:
1.the exact population of koalas in 2022;
2022:= .
2.the number of years it will take for the koala population to reduce to half of its number in 2018.
