How many composite numbers are between 1 and 50?

2 Answers
Shwetank Mauria · 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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