Math 081 Final Review Solutions

1.	 
      
2.	
	 or alternate method: 

3.	

4.	  

5.	
  	
6.	 
7.	

8.	

9.	
     or alternate method: 

10.	     

11.	        

12.	

13.	

14.	a. 

      b.	

15.	 in2
        C = 2r = 2(3.14)11 = 69.08in
16.	a.	

		

	b.	

17.	 a. one hundred and four thousand, five hundred seventy-two.
      
      b.	six and two hundred thirteen thousandths

18.	 
== 415.643in2

19.	 7.8mg = = .0078g
20.	2.4liters = 2.4L= 2400ml

21.	per notebook

22.	 .3x = 16.2

23.	

       

24.	

25.	A regular hexagon has 6 sides, all the same length, so the perimeter is 6 times the side length. 

26.	= = 57
									 
27.	Fred has to pay back $1200 + $80 = $1280. His monthly payment is:
	= $128
							
28.	. The approximation is 

29.	  =  = =

30.	74% = = 

31.	 978%  =  = =

32.	$= $51

33.	$1200(.2) = $240 is the discount. So the sale price is $1200 - $240 = $960

34.	

	

35.	 1.02 = =

36.	 

	   

37.	 Interest is  $7400(.15)(4) = $4440. She pays back $7400 + $4440 =$11840

38.	Check –1: 4(–1) + 9 = 3 – 2(–1)?
		– 4 + 9 = 3 – – 2?
		     5    =      5 yes
      Check 0: 4(0) + 9 = 3 – 2(0)?
		0 + 9 = 3 – 0?
		    9      3 no
      Check 1: 4(1) + 9 = 3 – 2(1)?
		4 + 9 = 3 – 2?
		    13      1 no
     So –1is the only number in the set that is a solution to the equation.
	
39.	18 + 25  53 – 12 = 18 +  – 12 = 18 + = 18 + 15 – 12 = 21

40.	120  0 undefined

41.	=  9

42.	12 – |– 18| = 12 – 18  = – 6

43.	(5 – 7)3(6 – 2)2 = (– 2)3(4)2 = –816 = –128

44.	

45.	mean: 
	median: in order –2, –7, 1, 2, 3, 4, 7, 11, 12. The middle number is 3, so 3 is the median.
	mode: There is no mode because each number appears only once.

46.	, and so the fractions are equal.
	Alternate method: 3655 = 1980 = 4544

47.	 

48.	a.	
	b.	
49.	
	  
	  4x + 6  =  10 – x
		5x = 4 

50.	a. area: in2           perimeter: in
b. area: 34 = 6cm2     
perimeter: First find the length of the hypotenuse. 
Then the perimeter is 3 + 4 + 5 = 12cm
					
51.	total hours = 3 + 4 + 4 + 4 + 2 = 17. 
	GPA = = 2 
	  
52.	

53.	1.572 = 21cm3

54.	
a.	3ft 8in + 4ft 9in = (3+ 4)ft + (8+9)in = 7ft + 17in = 7ft + 12 in + 5in = 8ft 5in

	b.	3cm + .25m = 3cm + .25m= 3cm + 25cm = 28cm