Common factor of 10 and 15 are ________

10 can be written as 10= $1\times 2\times 5$

15 can be written as 15= $1\times 3\times 5$

The product of all common prime factors is the HCF.

The common prime factors in this example are 5.

Here, the common factor of 10 and 15 is 5.