Inverse variation: y=k/x
1. plug in the values: (15,1)
1=k/15
2. solve for k
3. Now, plug in what you can for the second point: (n,5)
5=k/n (if you do the step above, you will know “k”.
4. Solve for “n”
In more conventional notation, ...
b(x) = -15x² +450x +325 . . . . 0 ≤ x ≤ 24
For 1990, x = 1990 - 1983 = 7
b(7) = -15·7² +450·7 +325 = 2740
The value of the card in 1990 was 2740.
The answer would probably be 18 degrees below normal because the absolute values of the rest are 8 not 18 which is the absolute value of 18 degrees below normal.
If a question has four possible answers, and you are strictly guessing regarding which of them is correct, then the chances of your choosing the correct one from the four is 1 in 4, or 0.25.
