The 80 Percent That Hides Two Outcomes
Read this paragraph, written by a student for a class magazine, and answer the questions that follow. The paragraph is complete and self-contained.
'Last spring our town planted 300 young trees along Main Street. By August, 240 of them had survived, a rate of 80 percent. The town council calls the project a success and plans 500 more trees next year. However, the survival rate for trees planted in concrete-heavy areas was only 55 percent, while trees in the park strip survived at 95 percent. The council's report does not separate these two groups. A success rate of 80 percent is respectable for a first effort, but it hides a serious problem: the trees are not failing evenly. If next year's 500 trees are planted in the same proportions, most of the losses will again fall on the blocks that can least afford shade.'
The student must answer questions from this paragraph only.
1. The council's supporters say the 80 percent figure is accurate. The author says it 'hides a serious problem.' Are these claims compatible? Explain using at least two numbers from the paragraph.
Read the worked answer
Yes, they are compatible. The figure is arithmetically accurate: 240 survivors out of 300 planted is 240/300 = 0.80, or 80 percent. But the same paragraph gives subgroup rates of 55 percent in concrete-heavy areas and 95 percent in the park strip. An overall rate is a weighted average, so it can be correct while concealing a large gap. The author does not deny the 80 percent; the criticism is that the council's report 'does not separate these two groups.' The judgement is therefore about completeness, not honesty. A reader who hears only 80 percent would predict uniform success; a reader who sees 55 and 95 would predict where the next 500 trees are most likely to fail. The word 'hides' means obscures, not fabricates.
2. A classmate concludes, 'The author is accusing the council of lying.' Is that conclusion supported? Distinguish what the text states from what it implies.
Read the worked answer
Not supported as stated. The text states that the council calls the project a success and plans 500 more trees, and that its report does not separate the two groups. It does not state that council members knew about the gap, that they calculated the 80 percent dishonestly, or that the number is wrong. 'Hides' can describe an omission that obscures a problem even when no one intends to deceive. To accuse the council of lying, a reader would need evidence of intent, such as a suppressed subgroup figure. The strongest supported inference is that the report's summary is incomplete and that the planting plan, if repeated proportionally, would reproduce the losses. The classmate has turned a criticism of reporting into a charge of motive, which the paragraph does not supply.
3. What does 'afford' mean in 'the blocks that can least afford shade,' and what assumption must be true for the final prediction to follow?
Read the worked answer
Here 'afford' does not mean 'have enough money.' It means 'bear the cost or loss of' - the blocks can least withstand the loss of shade. The prediction is conditional: if next year's 500 trees are planted 'in the same proportions,' then roughly the same share will go to concrete-heavy areas, where survival was 55 percent. The argument also assumes that the concrete-heavy blocks are the ones with the least existing shade and the least capacity to absorb tree loss; otherwise 'least afford shade' would not follow from the survival data alone. The paragraph gives the proportion condition explicitly but leaves the shade-need premise implicit. A careful answer should mark that second premise as an assumption rather than a stated fact.