Question 6
(a) State four characteristics of igneous rocks. . (4 marks)
(b) The table below illustrates the combined demand and supply schedule for maize.
Use it to answer the questions that follow.
Price |
Quantity of maize demanded |
Quantity of maize supplied (kg) |
20 |
50 |
340 |
16 |
70 |
300 |
12 |
125 |
250 |
8 |
200 |
200 |
4 |
350 |
130 |
(i) Draw the demand and supply curves to show the equilibrium price of maize.
(8 marks)
(ii) Determine the excess demand for maize at a unit price of ₦4. (3 marks)
(d) Determine the excess supply for maize at a unit price of ₦12. (3 marks)
Observation
- Question 6 was avoided by many candidates and marks were below average for most candidates. Most candidates were unable to state the characteristics of igneous rocks.
- Only few candidates were able to draw the equilibrium demand and supply curve for maize.
- Many candidates could not attempt the calculations on the excess demand and supply for maize.
The expected answers include:
6. (a) Charateristics of igneous rocks
- Formed from molten magma/volcanic eruption;
- Crystalline in nature;
- Resistant to weathering and erosion;
- Contains mainly primary minerals;
- Coarse or fine grained particles which is visible;
- Light or dark coloured;
- They are very hard.
(b) (i) Demand and supply curves for maize
