Plz solve this question in easy way , I wish you some this question soon for me I don`t get my correct answer

Take a right angled triangle....OAB where A=90, and angle AOB is 45 and the side AB as 20. Then using tan 45 we get AO also as 20. Extend AO to O` so that AO`B is 30. The distance oo`is X. Using tan 30 we get:- tan30=OA which is 20/AO` which is 20 + X.on solving this equation we get X as 20(√3-1). This is the distance travelled by the bird in 1sec. So speed= dist/time.so the ans is 20(√3-1)