D2 June 2007 Q4
4. A group of students and teachers from a performing arts college are attending the Glasenburgh drama festival. All of the group want to see an innovative modern production of the play ‘The Decision is Final’. Unfortunately there are not enough seats left for them all to see the same performance.
There are three performances of the play, 1, 2, and 3. There are two types of ticket, Adult and Student. Student tickets will be purchased for the students and Adult tickets for the teachers.
The table below shows the price of tickets for each performance of the play. There are 18 teachers and 200 students requiring tickets. There are 94, 65 and 80 seats available for performances 1, 2, and 3 respectively.
| Adult | Student | |
|---|---|---|
| Performance 1 | £5.00 | £4.50 |
| Performance 2 | £4.20 | £3.80 |
| Performance 3 | £4.60 | £4.00 |
| Adult | Student | Dummy | Seats available | |
|---|---|---|---|---|
| Performance 1 | £5.00 | £4.50 | ||
| Performance 2 | £4.20 | £3.80 | ||
| Performance 3 | £4.60 | £4.00 | ||
| Tickets needed |
(2)
After a further iteration the table becomes:
| Adult | Student | Dummy | |
|---|---|---|---|
| Performance 1 | 73 | 21 | |
| Performance 2 | 18 | 47 | |
| Performance 3 | 80 |
| Scheme | Marks | |||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| B2, 1, 0 | |||||||||||||||||||||||||
| (2) |
| Scheme | Marks |
|---|---|
| total supply > total demand | B1 |
| (1) |
| Scheme | Marks | ||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
(c)(d)
| B1 | ||||||||||||||||
| (1) |
Notes
The scheme marks (c) and (d) together; the north-west corner solution earns the B1 for (c).
| Scheme | Marks | ||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| \(S(1) = 0\quad D(A) = 5\) \(S(2) = -0.7\quad D(S) = 4.5\) \(S(3) = -0.5\quad D(D) = 0.5\) | M1 A1ft | ||||||||||||||||||||||||||||||||
| \(I_{1D} = 0 - 0 - 0.5 = -0.5^*\) \(I_{2A} = 4.2 + 0.7 - 5 = -0.1\) \(I_{2D} = 0 + 0.7 - 0.5 = 0.2\) \(I_{3A} = 4.6 + 0.5 - 5 = 0.1\) | A1 | ||||||||||||||||||||||||||||||||
| M1 A1ft A1 | ||||||||||||||||||||||||||||||||
| (6) |
| Scheme | Marks |
|---|---|
| \(S(1) = 0\quad D(A) = 4.9\) \(S(2) = -0.7\quad D(S) = 4.5\) \(S(3) = -0.5\quad D(D) = 0\) | M1 A1 |
| \(I_{1A} = 5 - 0 - 4.9 = 0.1\) \(I_{2D} = 0 + 0.7 - 0 = 0.7\) \(I_{3A} = 4.6 + 0.5 - 4.9 = 0.2\) \(I_{3D} = 0 + 0.5 - 0 = 0.5\) | A1 |
| Optimal since all I’s \(\geqslant 0\) | A1 |
| cost £902.70 | M1 A1 |
| (6) | |
| (16 marks) |
Notes
(Corrected from the printed mark scheme: the shadow costs \(D(S) = 4.5\) and \(D(D) = 0\) are both printed as \(D(B)\).)