Need SQL Help

select ename,sal,job and deptno of the employees

where job belongs to manager and president and tax is more than 1000..

logic to calculate tax is follows

if salary is more than 4000 then tax is 33% of sal

if salary is more than 2500 then tax is 25% of sal

if salary is more than 1500 then tax is 20%

can you help me out to write query in sql for above question