Solve this one!!
If you are a developer, never mind, maybe 1 hour;
If you are an Architect, perhaps you will need 3 hours;
If you are a Doctor, perhaps you will need 6 hours;
If you are an Accountant, maybe 3 months;
If you are a Lawyer, maybe you can never find the answer.
|---+----+----+------+------|
| 2 | 3 | 4 | 15 | 12 |
|---+----+----+------+------|
| 3 | 4 | 5 | 28 | 20 |
|---+----+----+------+------|
| 4 | 5 | 6 | 45 | 30 |
|---+----+----+------+------|
| 5 | 6 | 7 | 66 | 42 |
|---+----+----+------+------|
| 6 | 7 | 8 | ? | 56 |
|---+----+----+------+------|