High school Undergrad. (yrs. 1-2) Undergrad. (yrs. 3-4) Graduate PhD
28 days $11 $13 $18 $23 $27
14 days $14 $15 $20 $25 $29
7 days $16 $17 $21 $27 $31
5 days $18 $19 $23 $29 $35
3 days $20 $24 $28 $33 $37
48 hours $24 $26 $30 $36 $45
24 hours $27 $30 $32 $39 $50
8 hours $34 $39 $41 $48 $58
4 hours $39 $43 $51 $61 $73