Math & Science ACT Workuot

(Marvins-Underground-K-12) #1
48 . H Given the area of the circle is 16π square meters, the radius is 4 meters. AC is the longest

chord in the circle, which is the diameter of the circle, so O can be labeled as the midpoint.

OA and OB are each 4 meters, so ΔOAB is an equilateral triangle whose angles measure 60°.

AOB + BOC = 180°, BOC so measures 120°, making the arc degree also 120°. Choice

(F) gives the measure of arc AB rather than BC. Choices (G) and (J) use an incorrect triangle.

49 . A A system of equations has no solutions if the equations have the same slope and different y-

intercepts. Two linear equations have the same slope if they have the same ratio of

coefficients for x and y. Set up a proportion of the coefficients: = . 12b = 24, so b = 2.

Choices (B), (C), (D), and (E) do not give slopes equal to that of the first equation.

50 . F The shading above the horizontal line segment means that the y-values, which represent the

number of pies Rebecca and Scott make, are never less than 1. In other words, they always

make at least 1 pie, which is (F).

51 . D The best way to approach this question, since it asks about the maximum, is check the

endpoints or extremes of the graph: (9,1) and (0,4). Using the provided expression for

weekly profit, 12(9) + 25(1) = $133, which is (B). Check the other extreme to see that 12(0)

+ 25(4) = $100, which is less than $133.

52 . K If Rebecca and Scott made 5 pies at 3 hours each and 3 dozen cookies at 1 hour each, then

they spent 18 hours baking that week. They donated $2 for every hour they spent baking, so

they donated $36. The question asks what percent of that week’s profit they donated, so

calculate that week’s profit. According to the provided expression for weekly profit, 12(3) +

25(5) = $161. The $36 donated, out of $161 earned, is approximately 22%, which is (K).

53 . A Following the formula provided, (w)(10) − (w)(w) = 25. Rearranging, 10w − w^2 = 25

becomes w^2 − 10w + 25 = 0. Factoring the quadratic into (w − 5)(w − 5) = 0, the only

possible value for w is 5, so the answer is (A).

54 . K This formula may look complicated, but if you’re careful with the pieces, this will be basic

golden-rule algebra. If x = B(1 + .2g)n, then divide both sides by (1 + .2g)n to get

= B, which is (K). If you find the algebra daunting, you can also plug in simple numbers and

find a target value for B.

55 . C The main things you know for sure about m and n are that m is negative, and n is positive.
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