Question 78·Hard·Command of Evidence
Percentage of Population Aged 65 and Over in Japan and Brazil, 1950–2050
| Year | Japan | Brazil |
|---|---|---|
| 1950 | 5 | 3 |
| 1980 | 9 | 4 |
| 2015 | 27 | 8 |
| 2050 (projected) | 37 | 23 |
Figures for 2050 are projections.
Over time, both Japan and Brazil have seen increases in the share of older adults. Japan’s share rose sharply in an earlier period than Brazil’s did. This difference in timing is shown most clearly by comparing the data from ______.
Which choice most effectively identifies the data that best illustrates this difference in timing?
For data-support questions about a trend’s timing, translate the claim into a measurable pattern (for example, “Japan increases a lot during an earlier span while Brazil increases only a little”). Then test each option by computing the change between the two years for each group and selecting the pair whose changes most directly match the claim.
Hints
Focus on the key idea
The sentence is about timing: Japan’s sharp increase happens earlier, while Brazil’s sharp increase happens later. Look for a time span where Japan rises steeply but Brazil does not.
Compare changes, not just end values
For each option, calculate how much Japan changes and how much Brazil changes between the two years.
Find the “Japan steep, Brazil not yet” span
Which pair shows Japan’s biggest jump happening while Brazil is still increasing only a little?
Step-by-step Explanation
Identify what kind of evidence the sentence is asking for
The sentence contrasts timing: Japan’s share of adults aged 65+ rises sharply in an earlier period, while Brazil’s sharp rise happens later. So we should choose a pair of years where Japan’s increase is steep but Brazil’s increase is still relatively small.
Compare the changes for each answer choice
Compute how much each country changes between the two years in each option:
-
Choice A: 1950 to 1980
- Japan: 5 → 9 (up 4)
- Brazil: 3 → 4 (up 1)
-
Choice B: 1980 to 2015
- Japan: 9 → 27 (up 18)
- Brazil: 4 → 8 (up 4)
-
Choice C: 2015 to 2050 (projected)
- Japan: 27 → 37 (up 10)
- Brazil: 8 → 23 (up 15)
-
Choice D: 1950 to 2050 (projected)
- Japan: 5 → 37 (up 32)
- Brazil: 3 → 23 (up 20)
Choose the comparison that best matches the timing contrast
We want a span where Japan is already rising steeply while Brazil is not yet rising steeply. From 1980 to 2015, Japan increases sharply (9 to 27) while Brazil increases only modestly (4 to 8), so the best pair is 1980 and 2015.