ACT Preparation / Unit 19 ACT 1812 worked example, 60 to 90 seconds
Describing a Trend
The idea
A trend question is answered in three steps. First, read the values in order of the horizontal quantity, from smallest to largest. Second, note each change, up, down or flat, and where any change of direction occurs. Third, choose the answer that describes the whole series, including any peak or leveling off, and reject answers built from only part of it.
In practice
Worked example: an invented table gives the rate of a reaction at 10, 20, 30, 40 and 50 degrees as 3, 8, 15, 11 and 4 units. In order, the rate rises from 10 to 30 degrees, peaks at 30, then falls through 50. The choices are: the rate increases with temperature; the rate decreases with temperature; the rate increases to a maximum near 30 degrees, then decreases; the rate does not change. The third is right; the first describes only the first half.
Where people slip
A rise-then-fall pattern defeats one-word answers. Check the last values before accepting "increases."
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
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