Grade 8 Answers


Grade Eight Answers


1)

Answer:

   1000.00 + 230.00 * 24 = $6520.00
   6250.00 - 5800.00 = $720.00 more for the installment plan. 


2)

Answer:

   To run the 200m:          1 min = 60s + 10s = 70s
   To run 200m with hurdles: 60s + 30s = 90s

   90s - 70s = 20s longer.


3)

Answer: A)

               |     PERCENTAGE          PERCENTAGE
               |   FOR FIRST TEST      FOR SECOND TEST	   DIFFERENCE
---------------+--------------------------------------------------------
MARK           |        40%                 80%                40% 
JAKE           |        50%                 90%                40%
MARILYN        |        30%                 90%                60%

B)

               |    30% of            70% of          Sum Final    
               |  first test        second test         Mark
---------------+--------------------------------------------------------
MARK           |     12%                56%              68%
JAKE           |     15%                63%              78%
MARILYN        |      9%                63%              72%

Jake did the best overall.


4)

Answer:

    Cher dated George.
    Brandan dated Melissa
    Connie dated Andrew
    Sam dated Kendra


5)

Answer:

    1 cut ---> 2 sheets
    2 cuts---> 4 sheets
    3 cuts---> 8 sheets
    4 cuts---> 16 sheets
    ...
    10 cuts--> 210 sheets	
    1024 (.01) = 10.24mm = 1.024 cm


6)

Answer:

    10 (45) + 10 (45) + 1 = 901

    1 + 10 * (the sum of the digits 1 to 9) + 10 * (the sum of the digits 1 to 9) = 901


7)

Answer:

    Let x = percent increase	
    4.00 * x = 5.00
    x = 5.00/4.00 * 100% = 125%
    10.00 * 125% = $12.50 is the new cost of cleaning a jacket


8)

Answer:

    On 4 sides 20cm of ribbon each = 80cm  on the top and bottom.
                         .5 * 10cm = 25cm
                          2 * 25cm = 50cm

    Total amount of ribbon 47cm + 50 cm + 80cm = 177cm = 1.77m


9)

Answer:


362 = 1296 cm2


10)

Answer:


                180 degrees - 120 degrees =  60 degrees
                180 degrees - 110 degrees =  70 degrees
                 60 degrees +  70 degrees = 130 degrees 
                180 degrees - 130 degrees =  50 degrees


11)

Answer:

    x / 25 = 72    
    x = 1800 = the sum of all the grades
    1800 - 36 + 86 = 1850
    1800 / 25 = 74%


12)

Answer:

    Let C = # of acorns Chip had and D = # acorns Dale had.
    Then C + 1 =  D - 1 ; D=! = 2(C-1).
    Solve to get C = 5 and D = 7.   


13)

Answer:

    45 degrees

    Percentages:
    $15/$120 *100% = 12.5%
    360 degrees * 12.5% = 45 degrees


14)

Answer:

   

    42 + 33 = ?2
    25 = ?2
    5km = ?                    3km + 5km = 8km

    She would have to walk an additional 4 kilometers to get home from where she met the dog.


15)

Answer:

    Areas:    semi circle:  area = Pi * radius squared
                                 = 1/2 Pi * r2
                                 = 1/2 Pi (2m)2
       		                 = 1/2 Pi (4m,sup>2)
                                 = 2Pi m2
              triangle   :  area = 1/2 base * height
                                 = 1/2 (3m)(4m)
                                 = 6 m2
              rectangle  :  area = (4m)(6m)
                                 = 24 m2

    Total area = 24 + 2Pi + 6 = 36.28 m2.

    Cost = $5.00/m * 36.28 m,sup>2 = $181.42


16)

Answer:

    Pythagorean Theorem

	x2 = 82 + 62			y2 = 32 + 42
	x2 = 64 + 36			y = 5 cm
	x = 10cm 
	LM = 10cm + 5cm = 15cm = 150mm


17)

Answer:

    1/4


18)

Answer:

    The snake is one meter long.
    100/2 = x/4.5

    x = 450/2 = 225cm high


19)

Answer:

    1st birthday -> $1
    2nd birthday -> $2
    3rd birthday -> $4

                    $8
                   $16
                   $32
                   $64
                  $128
                 ------
                  $255


20)

Answer:

    Mathematics             Science              Art
         |                     |                  |
     Ms. Smith             Ms. Gracia        Ms. O'Leary    


21)

Answer:

    2/3 * 27 = # of Charle's comics = 18
    Jim has 3 * 18 = 54 comic books


22)

Answer:

     6 for $10            4 for $10.00
     1 for $10/6
     1 for $2.50

     x$2.50 - x$10/6 = $60.00

     .83x = $60.00
     x = 72 handkerchiefs.


23)

Answer:

    How many hours in total does it take you?

    160km/80km/hr = 2hr           160km/48km/hr = 3.33hr

    Average speed = (160 + 16)0/(2 + 3.33) = 60km/hr


24)

Answer:

    Find out how many disks for each weight 2kg and 5kg.

    x = # of 2kg disks
    14 - x = # of 5kg disks

    2kg = 5kg(14-x)
    2kg * x = 5kg(14 - x)
    2kg * x = 70kg - 5kg * x
    7kg * x = 70kg
    x = 10

    10 = # of 2kg disks
    4  = # of 5kg disks

    Total weight = 2kg (10) + 5kg (4)
                 = 40kg


25)

Answer:

One way is to lay the 12cm and 15cm carrots end to end. Then lay the 10cm carrot next to the other two and mark off the distance.

12 15

|------------|--------------| |----------|////////////////| 10 17

26)

Answer:

  • -You must be a girl,
  • -Your brother Pat is younger than you,
  • -Connie is a younger sister,
  • -Jennifer must be the mother,
  • -You are Sharon.


    27)

    Answer:

        DE = 5cm
        BE = 10cm
        BC = 2.5cm
    


    28)

    Answer:

    a)
        445 - 157 = 288 pages left
        288/24 = 12
        It will take twelve days to finish the book.
    
    b)
        288/9 = 32 pages a day
    


    29)

    Answer:

               2 | 7 | 3
              -----------
               4 | 6 | 9
              -----------
               1 | 8 | 5
    
    
               6 | 1 | 2
              -----------
               4 | 5 | 7
              -----------
               3 | 9 | 8
    
    
               1 | 3 | 5
              -----------
               2 | 4 | 6
              -----------
               7 | 8 | 9
    


    30)

    Answer:

    	1st -> 15
    	2nd -> 19
    	3rd -> 23
    	4th -> 27
    	5th -> 31
    	6th -> 35
           -----------
             150 pies
    


    31)

    Answer:

         $1.70/.5 = x/ 2.5 
              .5x = 4.25/.5
                x = $8.50 
    


    32)

    Answer:

    
        width  = 6cm
        length = 10cm
        height = 12cm
    
        6cm * 10cm * 12cm = 720 cm3
    


    33)

    Answer:

    	On each side:
    	48/4 = 12 posts (4 are shared corner posts)
    	(12-1) * 5 = 55m on each side   (there are 12-1, 5m sections on each side)
    	Area = 55m * 55m = 3025m2
    


    34)

    Different Answers:

        1)  1*1 + 1*1 + 9*9
        2)  3*3 + 5*5 + 7*7
        3)  4*4 + 3*3 + 7*7 + 3*3
    


    35)

    Answer:

        17000/7*60 + 27 = 38.03 sit-ups/min -> Record
    
        17000/40 = 425 minutes = 7 hours and 5 minutes
        Your rate is better!!
    


    36)

    Answers:

             x = # of incorrect answers
    	7x = # of correct answers
    	120 = 8x
    	x = 15 incorrect
    	7*15 = 105 correct
    


    37)

    Answer:

    			1 ->  4
    			2 ->  9
    			3 ->  16
    			4 ->  25
    			5 ->  36
    			6 ->  49
    			7 ->  64
    			8 ->  81
    			9 ->  100
    		    ----------------
                         385 grapefruit
    


    38)

    Answer:

    	x squared = 22 + 1.52      Perimeter = 4(2.5) = 10cm
    	        x = 2.5
    
    	Area of a triangle = 1/2*bh
                               = .5 * 2 * 1.5
                               = 1.5
    
    	Area = 4(1.5) = 6 cm2
    


    39)

    Answer:

    	x  = width
    	4x = length
    
    	x*4x = 100 meters squared
    	4x*x = 100
    	 x*x = 25
    	   x = 5 = width
    	  4x = 20 = length
    


    40)

    Answer:

        Time = 4112/760 = 5.4 hrs ; 5.4hrs * 60 = 324 mins
        Time = 4112/904 = 4.55 hrs = 273 mins
    
        Sydney to Saskatoon = 324 mins
        Saskatoon to Sydney = 273 mins
        The trip West is 51 minutes longer
    


    41)

    Answer:

        2025 > x > 1936
        1950 = 13 * 150
    


    42)

    Answer:

        10cm = diameter B
         5cm = diameter C
    
           A = Pi * r2
             = Pi (2.5cm)*(2.5cm)
             = 6.25*Pi cm2
    


    43)

    Answer:

        Area of sides = 3*4 - 1*1 - 3*1 = 8
        Area of front and back = 3*4 = 12
        Area of top and bottom = 3*4 = 12
    
                Total = 2*8 + 2*(12) + 2*(12) = 64cm2
    


    44)

    Answer:
    Moon		Earth		Sun
    

    \ / \ /

    3.84*105 km 1.49*108 km

    1.49*108/3.84*105=388 times as great

        
    


    45)

    Answer:

        Total:  $54.77
                $78.20
                $38.25
             +  $39.50
             -----------
               $210.72
    
        210.72/2 = 105.36
    
        Angie Owes 132.97 - 105.36 = $27.61
    


    46)

    Answer:

         x = age of daughter
        4x = fathers age
        4x + 20 = 2(x + 20)
        4x + 20 = 2x + 40
        2x = 20
         x = 10
        
        I am 10, my father is 40
    


    47)

    Answer:

        a)  255/256
        b) (2n -1) / (2n)
    


    48)

    Answer:

        2.5/12 = x/30
             x = 6.25km 
               = 6.25*103m
    


    49)

    Answer:

    26 hens and 12 hogs


    50)

    Answer:

    27 pineapples


    51)

    Answer:

    5.8cm