[填空题]
The Australian Koala Founda y54c/uzqotvm 3sp0 bb+6 vnh6tion estimates that there are about 45000 koalas jzq k 8e:: / qz7j8xgeu9.bducleft in the wild in 2019. A year before, in 2018, the population of koalas was estimated as 50000. Assuming the population of koalas continues to decrease by the same percentage each yea.g7j: qcdx:e8u 89 uzqe/bjkzr, 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.
