This set mixes the five skills in food, water and energy systems: reading water data, explaining food constraints, tracing energy, comparing approaches and questioning evidence. All numbers are invented for practice.
Work in order from easy to harder, with a calculator and a pencil. Cover the answers until you have written your own. The statistics and distribution explorer and food-web and energy-flow explorer help you check working, and the mistake log is the place to record slips.
Questions
Q1 (easy). In one month, rainfall is 60 mm and evapotranspiration is 40 mm. Find the water balance and say whether it is a surplus or a deficit.
Show answer
60 − 40 = +20 mm, a surplus.
Q2. Three dry-season months have rainfall of 30, 45 and 80 mm and evapotranspiration of 70, 60 and 50 mm. Find each monthly balance and the total.
Show answer
Monthly: 30 − 70 = −40; 45 − 60 = −15; 80 − 50 = +30. Total = −40 − 15 + 30 = −25 mm.
Check: rainfall 155, evapotranspiration 180, and 155 − 180 = −25.
Q3. A district grows 36,000 tonnes of maize on 12,000 hectares. Find the yield.
Show answer
36,000 ÷ 12,000 = 3 tonnes per hectare.
Q4. A city of 200,000 people eats 100 kg of rice each per year. Local farms harvest 24,000 tonnes, and 10% is lost after harvest. Is there a surplus or a shortfall, and how large?
Show answer
Demand: 200,000 × 100 kg = 20,000,000 kg = 20,000 tonnes. Supply after loss: 24,000 × 0.9 = 21,600 tonnes. Surplus = 21,600 − 20,000 = 1,600 tonnes.
Q5. A power plant takes in 400 units of fuel energy and produces 100 units of electricity. Calculate efficiency and the energy lost as waste heat.
Show answer
100 ÷ 400 = 0.25, so 25%. Waste heat = 400 − 100 = 300 units.
Q6. A wind farm has a capacity of 10 MW and runs at an average of 30% of capacity over one day. How much energy does it deliver in 24 hours?
Show answer
Average power = 10 × 0.3 = 3 MW. Energy = 3 × 24 = 72 MWh.
Q7. Explain, in three linked steps, how a long drought could reduce the food available to a farming region.
Show answer
Low rainfall reduces soil moisture and river flow, so crop yield per hectare falls. With the same area farmed, total harvest is lower, so the food available locally is less than in a normal year. A fourth link could add that households with less income may find it harder to buy imported food.
Q8. A farm irrigates 50 hectares. Flood irrigation uses 12,000 m³ per hectare per season and drip irrigation uses 7,000 m³. Calculate the water saved by drip irrigation and the percentage saving.
Show answer
Flood: 12,000 × 50 = 600,000 m³. Drip: 7,000 × 50 = 350,000 m³. Saving = 250,000 m³. Percentage = 250,000 ÷ 600,000 = 0.4167, so about 42%.
Q9. Write one comparative sentence using the Q8 figures.
Show answer
Drip irrigation uses 7,000 m³ per hectare, whereas flood irrigation uses 12,000 m³, so drip saves about 42% of the water on the same land.
Q10. Annual rainfall in four years was 800, 760, 840 and 900 mm. Find the mean and the median.
Show answer
Total = 800 + 760 + 840 + 900 = 3,300. Mean = 3,300 ÷ 4 = 825 mm. Ordered: 760, 800, 840, 900. Median = (800 + 840) ÷ 2 = 820 mm.
Q11 (harder). A village says: “Our new solar panels make our energy supply fully sustainable.” Give three pieces of missing evidence.
Show answer
Any three of: what share of total demand the panels supply; whether the supply works at night or in cloudy weather and what covers it; the materials, energy and disposal involved in making and replacing panels; the baseline year and time period; who measured the figures; the effect on land use or other resources. Say the claim does not show these, rather than calling it false.
If you got these wrong
- Q1, Q2, Q10 (balances, sign errors, averages): revisit interpreting a water-balance dataset.
- Q3, Q4, Q7 (yield, supply against demand, chains): revisit explaining a food-supply constraint.
- Q5, Q6 (efficiency, MW and MWh): revisit tracing an energy-system input and output.
- Q8, Q9 (comparisons): revisit comparing management approaches descriptively.
- Q11 (claims): revisit identifying missing evidence.
If errors are mostly in arithmetic, slow down and write the units on every line. If they are mostly in explanation, rewrite your answer using the chain and comparison patterns from the lessons.
Working through these with a teacher who sees your handwriting and your reasoning is the main thing online one-to-one Geography tuition adds.