Numerical Reasoning
Understanding Numerical Reasoning
Numerical reasoning tests measure your ability to work with numbers, interpret data, and solve problems. For firefighters, this might involve calculating water pressure, hose lengths, response times, or interpreting tables and graphs.
Key concepts include:
- Basic arithmetic: Addition, subtraction, multiplication, division.
- Percentages, ratios, and proportions: Commonly used in equipment mixing or resource allocation.
- Data interpretation: Reading tables, charts, and graphs accurately.
- Unit conversions: e.g., litres to gallons, metres to feet.
- Averages: Mean, median, mode.
Common Traps
- Misreading units: Failing to convert units before calculating.
- Calculation errors: Rushing and making simple mistakes.
- Misinterpreting graphs: Overlooking scale or labels.
- Percentage increase vs. decrease: Confusing the two.
- Average vs. total: Mixing up sum and mean.
Worked Example
A fire engine carries 1800 litres of water. If it uses 25% of its water, how many litres remain? A) 450 B) 1350 C) 1500 D) 1750
Answer: B. 25% of 1800 = 450. Remaining = 1800 - 450 = 1350 litres.
Rule of thumb: For percentage problems, identify the base and the operation (increase/decrease) before calculating.