# Greatest Common Factor of 3 Numbers Online Quiz

Following quiz provides Multiple Choice Questions (MCQs) related to Greatest Common Factor of 3 Numbers. You will have to read all the given answers and click over the correct answer. If you are not sure about the answer then you can check the answer using Show Answer button. You can use Next Quiz button to check new set of questions in the quiz. Q 1 - The greatest common factor of 18, 30, 45 is

A - 3

B - 5

C - 6

D - 9

### Explanation

Step 1:

The prime factorization of 18 is

18 = 2 × 3 × 3

The prime factorization of 30 is

30 = 2 × 3 × 5

The prime factorization of 45 is

45 = 3 × 3 × 5

Step 2:

The greatest common factor of 18, 30 and 45 is therefore 3.

Q 2 - The greatest common factor of 21, 36, 42 is

A - 2

B - 3

C - 6

D - 7

### Explanation

Step 1:

The prime factorization of 21 is

21 = 3 × 7

The prime factorization of 36 is

36 = 2 × 2 × 3 × 3

The prime factorization of 42 is

42 = 2 × 3 × 7

Step 2:

The greatest common factor of 21, 36 and 42 is therefore 3.

Q 3 - The greatest common factor of 24, 32, 48 is

A - 2

B - 4

C - 6

D - 8

### Explanation

Step 1:

The prime factorization of 24 is

24 = 2 × 2 × 2 × 3

The prime factorization of 32 is

32 = 2 × 2 × 2 × 2 × 2

The prime factorization of 48 is

48 = 2 × 2 × 2 × 2 × 3

Step 2:

The greatest common factor of 24, 32 and 48 is therefore 8.

Q 4 - The greatest common factor of 26, 52, 78 is

A - 13

B - 17

C - 26

D - 19

### Explanation

Step 1:

The prime factorization of 26 is

26 = 2 × 13

The prime factorization of 52 is

52 = 2 × 2 × 13

The prime factorization of 78 is

78 = 2 × 3 × 13

Step 2:

The greatest common factor of 26, 52 and 78 is therefore 26.

Q 5 - The greatest common factor of 28, 49, 84 is

A - 7

B - 12

C - 14

D - 21

### Explanation

Step 1:

The prime factorization of 28 is

28 = 2 × 2 × 7

The prime factorization of 49 is

49 = 7 × 7

The prime factorization of 84 is

84 = 2 × 2 × 3 × 7

Step 2:

The greatest common factor of 28, 49 and 84 is therefore 7.

Q 6 - The greatest common factor of 36, 48, 120 is

A - 9

B - 12

C - 15

D - 18

### Explanation

Step 1:

The prime factorization of 36 is

36 = 2 × 2 × 3 × 3

The prime factorization of 48 is

48 = 2 × 2 × 2 × 2 × 3

The prime factorization of 120 is

120 = 2 × 2 × 2 × 3 × 5

Step 2:

The greatest common factor of 36, 48 and 120 is therefore 12.

Q 7 - The greatest common factor of 34, 85, 136 is

A - 2

B - 5

C - 8

D - 17

### Explanation

Step 1:

The prime factorization of 34 is

34 = 2 × 17

The prime factorization of 85 is

85 = 5 × 17

The prime factorization of 136 is

136 = 2 × 2 × 2 × 17

Step 2:

The greatest common factor of 34, 85 and 136 is therefore 17.

Q 8 - The greatest common factor of 36, 60, 144 is

A - 8

B - 9

C - 12

D - 15

### Explanation

Step 1:

The prime factorization of 36 is

36 = 2 × 2 × 3 × 3

The prime factorization of 60 is

60 = 2 × 2 × 3 × 5

The prime factorization of 144 is

144 = 2 × 2 × 2 × 2 × 3 × 3

Step 2:

The greatest common factor of 36, 60 and 144 is therefore 12.

Q 9 - The greatest common factor of 72, 96, 180 is

A - 12

B - 18

C - 24

D - 36

### Explanation

Step 1:

The prime factorization of 72 is

72 = 2 × 2 × 2 × 3 × 3

The prime factorization of 96 is

96 = 2 × 2 × 2 × 2 × 2 × 3

The prime factorization of 180 is

180 = 2 × 2 × 3 × 3 × 5

Step 2:

The greatest common factor of 72, 96 and 180 is therefore 12.

Q 10 - The greatest common factor of 90, 150, 225 is

A - 10

B - 15

C - 18

D - 25

### Explanation

Step 1:

The prime factorization of 90 is

90 = 2 × 3 × 3 × 5

The prime factorization of 150 is

150 = 2 × 3 × 5 × 5

The prime factorization of 225 is

225 = 3 × 3 × 5 × 5

Step 2:

The greatest common factor of 90, 150 and 225 is therefore 15.

greatest_common_factor_of_3_numbers.htm