Mini Exam 61 — Timed Mini Exams

Questions in this quiz (9)

1. The internet charges from Company A, $$a$$, and Company B, $$b$$, both in dollars, are represented by $$a=2t+30$$ $$b=3t+20$$ as functions of time $$t$$, in days. What is the internet charge, in dollars, of Company B when it exceeds the charge of Company A by $$\$40$$?

   • 170

2. Which pair of points could lie on a quadratic function if its vertex is $$(4,8)$$?

   • $$(3,8)\text{ and }(5,8)$$
   • $$(2,9)\text{ and }(6,9)$$
   • $$(-2,6)\text{ and }(4,6)$$
   • $$(1,4)\text{ and }(7,10)$$

3. If $$f(x)=x^2-9$$ and $$f(g(x))=x^2+6x$$, which of the following is $$g(x)$$?

   • $$x+5$$
   • $$x+3$$
   • $$x^2+3$$
   • $$\sqrt{x+6}$$

4. The number of bacteria in a petri dish at the start of an experiment was $$N_0$$. For every $$20$$-day period, the number of bacteria decreases by $$4\%$$ of the number from $$20$$ days before. Which equation represents the number of bacteria left, $$N_t$$, after $$t$$ days?

   • $$N_t=N_0(0.96)^{20t}$$
   • $$N_t=N_0(0.96)^{t/20}$$
   • $$N_t=N_0(0.04)^{20t}$$
   • $$N_t=\frac{t}{20}(0.96N_0)$$

5. The mean length of $$10$$ fish John caught is $$12.3$$ centimeters. If the longest fish is removed, the mean length of the remaining $$9$$ fish becomes $$11$$ centimeters. What is the length of the longest fish that was removed?

   • $$20$$
   • $$22$$
   • $$24$$
   • $$26$$

6. Which of the following equations best models the data shown in the scatterplot?

   • $$y=3x+0.5$$
   • $$y=\frac13(2^x)$$
   • $$y=2^x$$
   • $$y=\frac13x+0.5$$

7. A researcher surveyed $$100$$ random parents picking up their children from school about whether they want construction of a new school. The researcher then reported that $$90\%$$ of citizens are in favor of building a new school. Which of the following is the reason why the conclusion is not reliable?

   • Sample size is too small for a city
   • Sample is biased because those who do not have children may not want a new school
   • Sample should have included only children
   • The population of a city

8. In the figure, line segment $$BC$$ is tangent to the circle with center at $$A$$. If $$AC=5$$ and $$BC=4$$, what is the diameter of the circle?

   • 6

9. In the figure, $$O$$ is the center of the circle. The measures of angles $$CAO$$ and $$CBO$$ are each $$30^\circ$$. What is the value of $$x$$?

   • 120