Answers to 7th. and 8th. Grades Problems 

If you find any mistakes, please contact us immediately. Thanks

Sheet # 1

1) Profit with positive numbers and loss by negative numbers.
a) + $3000
b) -$6000
c) +100 feet
d) - 50 feet
e) - 15 yards
f) + 10 yards
g) East: + 2miles, West : -5 miles

2) B2: - 2
B1: - 1
Floor 1: +1
Floor 2: +2
Floor 3: +3

 Sheet # 2

1)
a) Profit with positive numbers and loss by negative numbers.
b) $114,000
c) $128,000
d) -$16,000
2)
a) Speet of the boat= + 4miles/hour

Water current= -2 miles/hour
b) 4 -2 = 2miles/hour

3)

a) 13,000 feet + 5,000 feet - 3,000 feet
b) 15,000 feet

 Sheet # 3

1)
a) x + 5
b) x -3
c) 8x
d) x/4
e) x + 10
f) 7x
g) x -11
h) x/2
i) x - 6
j) x -9

2)
a) The number increased by 1
b) The numer decreased by 3
c) The product of 2 and x
d) The number 18 divided by x
e) The product of 4 and x
f) The number decreased by 6
Sheet # 4

1)
a) d + 5
b) d + d +5

2)
a) 10d
b) q/4
c) 3y
d) 5n+1
e) (f-3)12

3)
a) n +4
b) n + 2n
c) n+7
d) n -5

 

 

 Sheet # 5

1)
a) n + 6
b) 8n
c) 8n + 1
d) 8n - 3
e) 8n/4
f) 2n + 3
g) 5(n + 2)
h) 7n - 10
i) 12/ (n + 1)

2)
a) Two times the number increased by 3
b) The three times the number subtracted from 6
c) Seven multiplied by a number decreased by one.
d) Number subtracted from 5 divided by two.
e) Two times the number increasec by fifteen

 Sheet # 6

1)
a) x +3
b) 10y
c) 25q
d) y + 5
e) z -6
f) q + 2q
g) n -6
h) n + 4n + n + 20
i) 5K + 10(K+1)
Sheet # 7

1) n +n+2 where n is the odd number.

2) n + n + 2+ n+ 4 where n is the even number.

3)10n, 10n + 10

4) n + ( n + 2) + (n + 4) where n is the odd number


 Sheet # 8

1)
a) x + 5 = 13
b) x - 3 = 7
c) 8x = 24
d) (x/4) = 9
e) x + 10 = 21
f) 7x = -35
g) x - 11 = -5
h) x -6=15
i) (x/2) = -7
j) (x+2) > 4
k) 5x<10

 Sheet # 9

1)
a) x/7 > 2
b) ( x -3) > 6
c) (x - 5) < 13
d) 3x > -9

2)
a) x >14
b) x > 9
c) x < 18
d) x > -3
Sheet # 10

1) n + 5 = 14, n = 9

2) 14 years

3) 7n = 35, n = 5

4) x + 7 = 20, x = 13

5) 12 n = 72, n = 6 feet

 Sheet # 11

1) 15 feet

2) x - 10 = 3, x = 13

3) 100n = 450, n = $4.50

4) 1 + 2n = 19, n = 9

5) 40t=240, t = 6 hours

 Sheet # 12

1)
a) x + x - 7 =21
b) x = 2(x-7)
c) 3(x-7) = 7 + x
d) 2x = 4 (x-7)

2)
a) m + 2m = 15
b) 2m - 5 = m
c) 2m = 5( m-3)
 

Sheet # 13

1)
a) 2w=(w+4)+3
b) 2(w+4) = (3w+1)
c) 2w + 2(w+4) = 36

2) n + 10 = 40, n = 30

3) (n/5) = 10, n = 50

4) n + n + 10 = 50, n = 20 inches

5) n + 5 + n = 35, n = 15 votes

  Sheet # 14

1) n + 2n < 27
n < 9

2) n + n + 1 n + 2 = 123
3n + 3 = 123, n = 40

3) 12n = 2400, n = $200


4) Father=32 years, son = 8 years

 Sheet # 15

1) 87.5%

2) 1/4, 1/3, 1/2, 3/4

3) 9307.5 pounds, 4.65 tons or 5 tons

4) 11 minutes and 34 seconds

5) 1.3 miles
Sheet # 16
1)
a) $21.24
b) Yes. Sales tax is added to the price after the discount.

2) m = g -1

3) 2.5 million bottles/hour

4) 16/36 = 4/9

5) $1.30

 Sheet # 17
1)
a) 6 + 9 + 8p = 25
b) p = $1.25

2) 0.47 and 3/5

 Sheet # 18
Sheet # 19

1)
a) 8640 bushels
b) $28,080

2) 14, 191,200

3) made $296.05

4) 49.26 days

 Sheet # 20

1) $24.30

2) m = 10

3) 1/3 = 0.33

4) 11 marathons

 Sheet # 21

1) $3240

2) 65 miles
Sheet # 22

1) black = 2/3, white = 1/3

2)
a) 1/2
b) No

3) Girl = 10/25, Boy = 15/25

4) Black = 8/48, White = 40/48

5) 1/2

 Sheet # 23

1)
a) 5/10 = 1/2
b) 1/2
c) 4/10
d) 1/5
e) 3/10
f) 1/5

2)
a) 12/25
b) 13/25
c) 9/25
d) 5/25
e) 3/25
f) 4/25

 Sheet # 24

1)
a) 1/5

b) 1/4

c) Card left in the draw pike are decreasing

d) 1/3

e) Chances are increasing as the cards left in the pile

are decreasing.
Sheet # 25

8 combinations

HTT
HTH
HHT
HHH
TTT
TTH
THT
THH

 Sheet # 26

1 coin = 2
2 coins = 4
3 coins = 8
4 coins = 16
5 coins = 32
6 coins = 64
7 coins= 128
8 coins = 256
9 coins = 512
10 = 1024

2) T = 2 N

 Sheet # 27

1) 4/52 = 1/13

2) 12/52

3) 5/6

4) 3/6

5) 1/36

6) 35/36
Sheet # 28

1) 1/8

2) 3/8

3) 1/32

4) 1/64

5) 1/128

  Sheet # 29

1) 5/35 = 1/7

2)
a) 5/10 = 1/2
b) 3/9 = 1/3
c) 2/8 = 1/4

3)
a) 6
b) 1/6
c) 5/6

  Sheet # 30

No worksheet at the moment

 
Sheet # 31

1) 573

2) 46

3) $460

4) $768.95

5) $50.77, Macy

 Sheet # 32

1) $1001.75

2) 23%, same % for both

3) $12,000

4) 45%

5) $913.10

 Sheet # 33

1) 1 X 2 X 3 X 4 X 5 X 6 X 7 = 5,040; there are

7 different barn animals that gathered around

Charlotte for the meeting.

 2) An acre is equal to 43,560 sq. feet. T

herefore, 43,560 sq. ft. X 3 acres = 130,680 sq. ft. 361.5 ft. X 361.5 ft. = 130,682.25 sq. ft. which is close to 130,680 ft. Each side of the county fair is about 361. 5 ft.

 3) At least 204 different squares.

64 1X1 squares

49 2X2 sq,

36 3X3 sq..

25 4X4 sq..

16 5X5 sq..

9 6X6 sq..

4 7X7 sq..

1 8X8 sq..

 4) Wilbur begins walking at 3 mph, next

he walks at 2 X 3 = 6 mph, then he walks at 2 X 6 = 12 mph,

and finally he walks 4 X 12= 48 mph.

 5) 3 X 2 X 1 = 6 different orders Charlotte could

have spun the messages.

6) Volume: 2 x 3.14 x 75 x 75 x 5 = 88312.5 cubic feet

Inner path circumference: 2 x 3.14 x 75 = 471 feet

Outer path circumference: 2 x 3.14 x 81 = 508.68 feet

7) Third angle= 180- (35 + 35) = 110 degrees

 Sheet # 34

1) 18 degrees

2) 25 degrees

3) - 2 degrees

4) - 5 degrees

5) 25 degrees
Sheet # 35

1) 4+6+8+10+12 = 40
40/5 = 8

2) -4-2+2+4+6+8 = 14
14/6

3) -10-8-6-4-2+2+4+6+8+10 = 0
0/10

4) -7-5-3-1+1+3+5+7+9+11 = 20
20/10 = 2

5) -11-9-7-5-3-1+1+3+5+7+9+11
+13 = 13

13/13 = 1

 Sheet # 36

1) 18 degrees

2) 18 degrees

3) 32 degrees

4) 22 degrees

5) 24 degrees

 Sheet # 37

1) -12

2) -8

3) -3

4) 13

5) 1

6) -3

7) 6

8) -4

9) 11

10) 7

 Sheet # 38

1) 76 points

2) 43 points

3) 50 points

4) 320 points
Sheet # 39

1) -113 m

2)
8848m, 6050m, -28m, -40m

3) 41+28-37 = 32m

4) 31,000 feet

 Sheet #40
1) 3%
2) 20 minutes 12 seconds
3) 28 minutes 48 seconds
4) 51 minutes 20 seconds

 Sheet #41
1) Tom= 2 m/s, Sam= 2m/s
2) Tom= 50 steps
Sam=100 steps
3) 4 steps/second
4) 2 steps/secon		 Sheet # 42

a) 6 hours 25 minutes
b) 2 hours
c) 50 cents
d) 95 cents
e) 5 cents
f) $3.75
g) $12.50
h) $8
i) $24.25
j) $15.75
k) 3 3/4 feet
l) 50 cm
m) 96 inches
n) 4 hours 45 minutes
o) 3 hours
p) $4.49 for 5 pounds
q) $5 for 750ml
r) 5 cups
s) 3 cups
t) 2 cups
u) 4 tsps
v) 1 hour
w) 30 minutes

 

 

 
Sheet #43

Mercury: 5.8 x 107

Venus 1.08 x 108

Earth 1,5 x 108

Mars 2.28 x 108

Jupiter7.78 x 108

Saturn 1.429x 109

Uranus 2.875 x 109

Neptune 4.504 x 109

Pluto 5.9 x 109

 Sheet #44

1) 3.0 x 108 m/s

2) 1.80 x 107 Km/minute

1.08 x 109 Km/hour

2.592 x 1010 Km/day

3) 9.46080 x 1012 m/s

 Sheet # 45

1) 1.4 x 106 Km

2) 1.4 x 109 Km

3) 5.0 x 104 degree

4) 4.5 x 109 years

5) 1.5 x 107 degree

 Sheet #46

1) 6.450 x 103 Km

2) 1.29 x 104 Km

3) 4.0506 x 104 Km

4) 1.50 x 108 Km

5) 1,16 x 104 earths

6)

a) 0.0218 x 1021 cubic meter

b) 1.404 x 1027 cubic meter

 Sheet 47

1) 1.483 x 108 sq. km

2) 2.966 x 107 sq. km

3) 1.187 x 108 sq. km

4) 6.0 x 1021
Sheet #48

1) 1.0 x 106 cubic cm

2) 3.0 x 109 grains/cubic cm

3) 3.0 x 109 seconds

4) 3.1536 x 107 seconds

5) 95.12 years

 Sheet 49

1) 2.0 x 108 m

2) 6.0 x 109 cubic meter

3) 1.8 x 1019

 Sheet #50

1) 1 x 10-8 cm

2) 0.5 x 10-8 cm

3) 1.0 x 1029

4) 105

5) 8.0 x 10-8 cm

 Sheet #51

 Sheet #52

1) 200 seconds
2) 80 seconds and 160 seconds
3) 61
4)
a) 15 minutes
b) 12 minutes
Sheet #53

The boys have two legs and dogs have 4 legs.

There are 5 possible answers:

8 boys and 6 dogs
2 boys and 9 dogs
10 boys and 5 dogs
4 boys and 8 dogs
6 boys and 7 dogs
 Sheet #54
1) 6 units, n+2
2) 14 units, 3n+2
3) 4n+2
 Sheet #55

18 figs

 Sheet #56

Apples= 22.22 pounds
Oranges= 77.78 pounds

 Sheet #57

n = father's age
Y = son's age

(1/6 + 1/12 + 1/7)n + 5+y+4=n
y=n/2

n=84 years
No worksheet Blank Sheet #58

20 pencils

Begining
Person 1= n and Person2= 3n
Transfer 1: n-5 and 3n+5
Transfer 2: 3n+5 - 3(n-5) = 20

 Sheet # 59

1) 2:5
2) 4/5
3) 27.11 feet

4) Average=17.4 points and 3 players
5) 5x3x3=45 choices

 Sheet # 60

1)
a) 1 apple/bag, 2, 3, 4, 6, 8 and 12
b) 6 apples/bag, 8 and 12
2)
2 persons with 13 roses each and 26 carnations each
13 persons with 2 roses each and 4 carnations each
26 persons with 1 rose each and 2 carnations each
3)
M&M= 5 boxes and Pototo= 6 boxes
Answers for sheet # 61 and beyond are at the bottom of each worksheet.
 . . . .