Keystone Test Algebra: Functions and Data 5

Question 1

The table shows costs: 1 item=$4, 2 items=$7, 3 items=$10, 4 items=$13. What is the cost for 10 items?

Accepted Answer

$31

Answer

The pattern is f(n) = 3n + 1; f(10) = 3(10) + 1 = 31.

Question 2

Which correlation coefficient indicates the strongest linear relationship?

Accepted Answer

r = -0.9

Answer

The correlation coefficient closest to -1 or 1 indicates the strongest relationship; r = -0.9 is closest to -1.

Question 3

f(x) = 4x - 3 and g(x) = f(x) + 5. What is g(x)?

Accepted Answer

4x + 2

Answer

g(x) = (4x - 3) + 5 = 4x + 2.

Question 4

A student scored 70, 80, 85, 90, and 100 on five tests. Which score, if added as a sixth test, would keep the mean at exactly 85?

Accepted Answer

85

Answer

Current sum = 425; for mean 85 with 6 scores, need sum = 510; sixth score = 510 - 425 = 85.

Question 5

Which graph represents a function that is decreasing over its entire domain?

Accepted Answer

y = -3x + 1

Answer

y = -3x + 1 has a negative slope (-3), so it decreases everywhere.

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