let newDepartments = departments.filter(department=>{
 return department.student<=5000;
});
//output:
  [
      { name: 'EEE',    student: 2000},
      { name: 'CSIT',   student: 5000},
      { name: 'ME',     student: 4500},
      { name: 'LAW',    student: 2500}
  ]