## Thursday, May 03, 2018

### Algebra 2 Problems of the Day

Daily Algebra 2 questions and answers.

More Algebra 2 problems.

August 2017, Part I

All Questions in Part I are worth 2 credits. No work need be shown. No partial credit.

10. lridium-192 is an isotope of iridium and has a half-life of 73.83 days. If a laboratory experiment begins with 100 grams of Iridium-192, the number of grams, A, of Iridium-192 present after t days would be A = 100(1/2)(t/73.83).
Which equation approximates the amount of Iridium-192 present after t days?

1) A = 100(73.83/2)t
2) A = 100(1/147.66)t
3) A = 100(0.990656)t
4) A = 100(0.116381)t

100(1/2)(t/73.83) = 100((1/2)(1/73.83)) (t)
(1/2)(1/73.83) = 0.99065551184
So 100(1/2)(t/73.83) = 100(0.990656) (t)

11. The distribution of the diameters of ball bearings made under a given manufacturing process is normally distributed with a mean of 4 cm and a standard deviation of 0.2 cm. What proportion of the ball bearings will have a diameter less than 3.7 cm?

1) 0.0668
2) 0.4332
3) 0.8664
4) 0.9500

You'll find "normCdf" using 2nd VARS, which gives you the DISTRIB menu, where it is option 2.
The 0 is your lower boundary, and 3.7 is your upper boundary. You want everything less than 3.7.
The 4 is your mean, and the 0.2 is your standard deviation.
You will get an answer of 0.066807.

12. A polynomial equation of degree three, p(x), is used to model the volume of a rectangular box. The graph of p(x) has x intercepts at −2, 10, and 14. Which statements regarding p(x) could be true? A. The equation of p(x) = (x − 2)(x + 10)(x + 14). B. The equation of p(x) = −(x + 2)(x − 10)(x − 14). C. The maximum volume occurs when x = 10. D. The maximum volume of the box is approximately 56

1) A and C
2) A and D
3) B and C
4) B and D