Victory for the ACT Student Text 15e

454 • C AMBRIDGE P RACTICE T EST R EINFORCEMENT

9. (D) (p. 380) Mathematics/Algebra and Functions/Evaluating, Interpreting, and Creating Algebraic Functions/Function Notation . Substitute 1 for x and evaluate: ( ) ( ) 1 2 1 2 3 2 3

( ) 1 2 1 − − = − − − − = − − − = − + = x x 2 1 2 1

The average is the sum of the numbers

divided by the number of elements: 3 2 1 3 4 + + − + + ( ) ( ) (

10. (G) (p. 380) Mathematics/Statistics and Probability/Measures of Center .

n

n

n

)

=

average

3

+

n

6 6

=

3

= +

n 2 2

11. (D) (p. 380) Mathematics/Algebra and Functions/Manipulating Algebraic Expressions/Evaluating Expressions . —„•–‹–—–‡ ͻ ˆ‘” x and evaluate: x x x 9 9 9 0 2 1 2 0 2 1 2 − −

1 9 + + = + + = + +

1

2

9

1

1 3 = + +

81

1

=

4 12. (G) (p. 380) Mathematics/Number and Quantity/Basic Arithmetic Manipulations . To add radicals, rewrite the ”ƒ†‹…ƒ†• ȋ–Š‡ —„‡”• —†‡” –Š‡ ”ƒ†‹…ƒŽ •›„‘ŽȌ ‹ –‡”• ‘ˆ –Š‡ •ƒ‡ —„‡”ǡ –Š‡…‘„‹‡ –Š‡…‘‡ˆϐ‹…‹‡–• ‘ˆ –Š‡ terms with the same radicands: 4 3 3 27 4 3 3 3 3 81

^ h

+

13 3 = + = + =

4 3 9 3

The average is the sum of the test scores

divided by the number of tests: 87 93 86 + + +

13. (D) (p. 381) Mathematics/Statistics and Probability/Measures of Center .

x

90 = =

average

4

( ) 4 90 87 93 86 = + + + = + = x 360 266 94

x

x

Each dime is ͳͲ…‡–•Ǥ Š—•ǡ Ͷ x

dimes would

14. (J) (p. 381) Mathematics/Number and Quantity/Rates and Proportions .

be x 4

cents.

10

cents

x

:

dimes

40

dime