ACT Preparation / Unit 19 ACT 1823 worked example, 60 to 90 seconds
Combining Two Figures
The idea
A question needing two figures is answered in three steps. First, find the shared quantity that links them. Second, read the first figure at the condition given, to get a value of the shared quantity. Third, carry that value into the second figure and read the answer, checking the units at each step.
In practice
Worked example: an invented figure 1 shows that a pond's water reaches 24 degrees in July. An invented figure 2 shows dissolved oxygen of 8 milligrams per liter at 24 degrees. So the oxygen in July is about 8 milligrams per liter. Neither figure alone answers the question; the temperature carries it from one to the other.
Where people slip
Carry the exact value read, not a rounded guess, when the second figure's curve is steep: a small change in the shared quantity can move the answer a lot.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
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