Combine data and logical constraints
Compare sources, calculate with correct units and test every condition before recommending an option.
Section READ-LOGIC · Combine data and logical constraints
Original StudyForA teaching and fictional practice scenarios. Model responses illustrate reasoning; other well-supported answers are possible. These tasks do not award Cambridge marks or grades. A broad topic map is not a complete current-affairs reading programme. Full-length unseen-paper practice, an authenticated reading bank and calibrated human assessment remain outstanding.
Before you begin
- Read short English passages
- Distinguish a claim from its supporting reason
Work on paper. Try each question before revealing help, and explain why your method works.
Quick readiness check
What should a reasoned answer do?
What you will learn
- Interpret data and related information from multiple sources
- Explain choices with calculations, constraints and relevant limitations
Use a table of conditions
Translate a decision into necessary conditions, preferences and a budget. An option can be cheap yet ineligible. Read all notes: a capacity figure may concern total attendance while an access requirement concerns a particular entrance or time.
Fictional rooms: A costs 240, seats 40 and is available at the required time; B costs 180, seats 30 and is also available. A meeting needs 35 seats and has a budget of 250. A meets both conditions; B fails capacity despite its lower price.
Calculate and explain
Label units and denominators. A rise from 40 to 50 is 10 people or 25%, not 10%. Distinguish a percentage-point change from a percentage change. For several sources, check whether populations, dates and definitions match before combining their figures.
Explain why an option meets each relevant condition and why a rejected one fails. Do not add assumptions such as an unmentioned second room or a price discount to make a preferred choice fit.
Sources for this lesson
Pause and explain
Why is the cheapest option not always the correct recommendation?
Worked example
Which room meets the fictional meeting requirements?
Show the worked solution
- Check capacity against 35.
- Check price against 250.
- Confirm time availability.
Answer Room A is feasible: 40 seats meets the 35-seat requirement, its cost of 240 is within the 250 budget, and it is available. Room B is cheaper but has only 30 seats, so it fails a necessary condition.
Try a topic test
Choose Easy, Normal or Difficult. Save your answers and open worked review after finishing.
Test this topic →From guided practice to a new situation
Write your answer and reasoning first. Use a hint only if you are stuck. The model solution is for self-checking; your written work is not automatically marked.
Guided: Using the room data, explain the choice in one concise paragraph.
Give me a hint
Use all stated conditions.
Compare my reasoning
- A has 40 seats versus 35 required.
- 240 is no more than the 250 budget.
- B’s 30 seats fails capacity.
Choose A because it seats 40 people, is available at the required time and costs 240 within the 250 budget. B costs less but seats only 30, below the required 35. The recommendation follows the given constraints without inventing an extra room or discount.
Look for these in your work
- Uses capacity
- Uses budget and time
- Explains rejection
Independent: Attendance rises from 40 to 50. Calculate the absolute and percentage increases and explain the denominator.
Give me a hint
Compare the increase with the original attendance.
Compare my reasoning
- 50−40=10.
- 10÷40=0.25.
- Multiply by 100 and label the quantities.
Attendance increases by 10 people and by 25%. The percentage uses the original 40 people as the denominator: 10 ÷ 40 × 100 = 25%. Calling the change 10% would confuse the absolute increase with its size relative to the starting attendance.
Look for these in your work
- Calculates the difference
- Uses the original denominator
- Labels the result
Application: Three helpers can each work at most four hours, and an event needs 14 helper-hours. Is the plan feasible without extra help?
Give me a hint
Compare total possible hours with the requirement.
Compare my reasoning
- Maximum hours are 3×4=12.
- 14−12=2 hours are missing.
- Do not invent longer shifts or another helper.
The plan is not feasible under the stated limit. Three helpers can provide at most 12 helper-hours, leaving a shortfall of two. The organisers need additional permitted help or a reduced requirement; they cannot solve the problem simply by assuming someone works beyond the four-hour limit.
Look for these in your work
- Calculates capacity
- Identifies the shortfall
- Preserves the conditions
Common mistakes
- Ignoring a necessary condition
- Combining incompatible figures
- Confusing percentage changes with absolute or percentage-point changes
What can you explain now?
Why is the cheapest option not always the correct recommendation?
Compare with the explanation
It may fail a necessary condition such as capacity or availability
Test feasibility before comparing preferences.
After trying it yourself, choose your next review. This is your self-assessment.
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Make it stick
Why is the cheapest option not always the correct recommendation?
If you needed the solution, close it and solve the problem again from a blank page. A correct answer is stronger when you can explain the reason for each step.