How many composite numbers are between 1 and 50?

2 Answers
Shwetank Mauria ยท EZ as pi
Apr 5, 2016

Total 33 composite numbers.

Explanation:

Between 1 and 50, we have following numbers as composite.

{4, 6, 8, 9, 10, 12, 14, 15, 16, 18, 20, 21, 22, 24, 25, 26, 27, 28, 30, 32, 33, 34, 35, 36, 38, 39, 40, 42, 44, 45, 46, 48, 49}

Total 33 composite numbers.

EZ as pi
May 26, 2017

48-15 = 33 composite numbers between 1 and 50

Explanation:

Composite numbers are those which have 3 or more factors:

Prime numbers are those which have exactly 2 factors:

There are more composite numbers than prime numbers, (can you explain why this is so?)

So it will be easier to count the prime numbers and subtract them.

There are 50 numbers FROM 1 to 50

Therefore there are 48 numbers BETWEEN 1 and 50. which are excluded.

There are 15 prime numbers less than 50, which are:

2,color(white)(.)3,color(white)(.)5,color(white)(.)7,color(white)(.)11,color(white)(.)13,color(white)(.)17,color(white)(.)19,color(white)(.)23,color(white)(.)29,color(white)(.)31,color(white)(.)37,color(white)(.)41,color(white)(.)43,color(white)(.)47

Therefore there are
48-15 = 33 composite numbers between 1 and 50.

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