[填空题]
The Australian Koala Foundation estimates that there are apd/l lg-cz.z*di(uq2s ,fuj;bout 45000 koaih: 5fd :s4j(jpkfz r i/uj/9dlas left in the wild in 2019. A year befojrf9d:5k su:(4 ifdh/zji/jpre, in 2018, the population of koalas was 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.
