Praxis Algebra I case studies
Praxis Algebra I · Put your knowledge to work in context.
Praxis Algebra I (5165) is a Praxis Subject Assessment from ETS, the same organisation behind the Praxis Core and other teacher-certification tests. Candidates take it to demonstrate subject knowledge in algebra for educator licensure; whether you need it, and the score you must reach, are set by your state rather than by ETS, so check your state's requirements before you register. The Praxis Algebra I case studies are 5 cases and about 3,551 words.
1Linear Cost Model Pushed Beyond Its Data
A print shop quotes a customer 290 for an order of 40 shirts and 650 for an order of 100 shirts of the same design, with one fixed setup charge and a constant per-shirt price. A student in a tutoring session models the total cost in dollars, C(n), for n shirts as C(n) = 6n + 50 and submits the model as complete.
728 words, about 4 min2Break-Even With an Unattainable Non-Integer Solution
A couple compares two reception venues for a wedding with a guest list that is not final. Venue A charges a 500 room fee plus 18 per guest.
688 words, about 3 min3Vertex Answer to an Intercept Question
A physical science class launches a model rocket from a platform 80 feet above the ground and records its height with a motion sensor. A quadratic model fits the data well: h(t) = -16t^2 + 64t + 80, where h is height in feet and t is seconds after launch.
744 words, about 4 min4Choosing Between Exponential and Linear Depreciation
A student analyzes the resale value of a car that cost 24,000 and, according to a used-car guide, loses 12% of its value each year. She writes V(t) = 24,000(0.12)^t, reports that the car will be worth 2,880 after one year, and concludes that the car 'loses value fast at first and then levels off.' A classmate disagrees and proposes L(t) = 24,000 - 2,880t, arguing that 'it loses the same 2,880 every year, so a line is simpler and just as good.' A table of values for the model year reads 24,000; 21,120; 18,586; 16,355.
645 words, about 3 min5Piecewise Delivery Fee and a Double-Counted Base
A food-delivery app charges 4.50 for the first 2 miles and 1.60 for each additional mile or part of a mile. A student writes f(m) = 4.50 + 1.60m for m ≥ 0, computes f(6) = 4.50 + 9.60 = 14.10, and submits it.
746 words, about 4 min