Math Practice Online: MathScore.com

Math Practice Online > free > lessons > Arizona > 8th grade > Proportions 1

If your child needs math practice, click here.

These sample problems below for Proportions 1 were generated by the MathScore.com engine.

Sample Problems For Proportions 1

Complexity=5, Mode=fraction

Solve for n
1.  
12
20
= n
10
n:
2.  
30
12
= n
8
n:

Complexity=8, Mode=ratio

Solve for n
1.   9 : 72 = n : 40
n:
2.   12 : 6 = n : 8
n:

Complexity=10

Solve for n
1.   70 : 50 = n : 30
n:
2.   21 : 70 = n : 60
n:

Complexity=20

Solve for n
1.  
10
14
= n
49
n:
2.   84 : 28 = n : 12
n:

Answers

Complexity=5, Mode=fraction

Solve for n
#ProblemCorrect AnswerYour Answer
1
12
20
= n
10
 n:
Solution
First simplify the fraction on the left: 12/20 = 3/5
3
5
= n
10
Cross Multiplication: First fraction numerator × second fraction denominator = first fraction denominator × second fraction numerator.
3 × 10 = 5n.
Dividing both sides by 5,
n = 3 × 10 ÷ 5 = 6

Alternate Explanation:
First simplify the fraction on the left: 12/20 = 3/5
3
5
= n
10

n
10		 =
3
5

n
10		 = 3 × 2
5 × 2		 =
6
10
#ProblemCorrect AnswerYour Answer
2
30
12
= n
8
 n:
Solution
First simplify the fraction on the left: 30/12 = 5/2
5
2
= n
8
Cross Multiplication: First fraction numerator × second fraction denominator = first fraction denominator × second fraction numerator.
5 × 8 = 2n.
Dividing both sides by 2,
n = 5 × 8 ÷ 2 = 20

Alternate Explanation:
First simplify the fraction on the left: 30/12 = 5/2
5
2
= n
8

n
8		 =
5
2

n
8		 = 5 × 4
2 × 4		 =
20
8

Complexity=8, Mode=ratio

Solve for n
#ProblemCorrect AnswerYour Answer
19 : 72 = n : 40
n:
Solution
Begin by rewriting the ratios as fractions: '9 : 72 = n : 40' becomes

9
72
= n
40
Then simplify the fraction on the left: 9/72 = 1/8
1
8
= n
40
Cross Multiplication: First fraction numerator × second fraction denominator = first fraction denominator × second fraction numerator.
1 × 40 = 8n.
Dividing both sides by 8,
n = 1 × 40 ÷ 8 = 5
#ProblemCorrect AnswerYour Answer
212 : 6 = n : 8
n:
Solution
Begin by rewriting the ratios as fractions: '12 : 6 = n : 8' becomes

12
6
= n
8
Then simplify the fraction on the left: 12/6 = 4/2
4
2
= n
8
Cross Multiplication: First fraction numerator × second fraction denominator = first fraction denominator × second fraction numerator.
4 × 8 = 2n.
Dividing both sides by 2,
n = 4 × 8 ÷ 2 = 16

Complexity=10

Solve for n
#ProblemCorrect AnswerYour Answer
170 : 50 = n : 30
n:
Solution
Begin by rewriting the ratios as fractions: '70 : 50 = n : 30' becomes

70
50
= n
30
Then simplify the fraction on the left: 70/50 = 7/5
7
5
= n
30
Cross Multiplication: First fraction numerator × second fraction denominator = first fraction denominator × second fraction numerator.
7 × 30 = 5n.
Dividing both sides by 5,
n = 7 × 30 ÷ 5 = 42
#ProblemCorrect AnswerYour Answer
221 : 70 = n : 60
n:
Solution
Begin by rewriting the ratios as fractions: '21 : 70 = n : 60' becomes

21
70
= n
60
Then simplify the fraction on the left: 21/70 = 3/10
3
10
= n
60
Cross Multiplication: First fraction numerator × second fraction denominator = first fraction denominator × second fraction numerator.
3 × 60 = 10n.
Dividing both sides by 10,
n = 3 × 60 ÷ 10 = 18

Complexity=20

Solve for n
#ProblemCorrect AnswerYour Answer
1
10
14
= n
49
 n:
Solution
First simplify the fraction on the left: 10/14 = 5/7
5
7
= n
49
Cross Multiplication: First fraction numerator × second fraction denominator = first fraction denominator × second fraction numerator.
5 × 49 = 7n.
Dividing both sides by 7,
n = 5 × 49 ÷ 7 = 35

Alternate Explanation:
First simplify the fraction on the left: 10/14 = 5/7
5
7
= n
49

n
49		 =
5
7

n
49		 = 5 × 7
7 × 7		 =
35
49
#ProblemCorrect AnswerYour Answer
284 : 28 = n : 12
n:
Solution
Begin by rewriting the ratios as fractions: '84 : 28 = n : 12' becomes

84
28
= n
12
Then simplify the fraction on the left: 84/28 = 12/4
12
4
= n
12
Cross Multiplication: First fraction numerator × second fraction denominator = first fraction denominator × second fraction numerator.
12 × 12 = 4n.
Dividing both sides by 4,
n = 12 × 12 ÷ 4 = 36

MathScore.com

Copyright Accurate Learning Systems Corporation 2008.
MathScore is a registered trademark.