With reference to the human resource planning example in Ch$.5($see Figure $5.3),$ please compute the number of external hires for each of the three jobs below.

$\backslash$table$[[,$Sales Rep,Supervisors,$\backslash$table$[[$Store$],[$Managers$]]],[$Predicted Future Needs,$250,50,30],[$Current employees,,,$],[$Currently in position,$100,20,10],[$Expected to quit,$20,4,3],[\backslash$table$[[$Expected to move internally$],[$to other jobs$]],30,10,0],[\backslash$table$[[$Expected to move internally$],[$to this job$]],0,30,10],[$External hiring need,?,?,?$]]$