We cannot answer this ! The word common indicates a comparison - you have not included another number to compare the factors of 75 with !
The highest common factor is 75
The highest common factor of 60 and 75 is 15
1 and the highest common factor is 15
It is 15
15
25
it is: 75
It is: 15
It is: 25
The GCF of 75 and 77 is 1.
HCF(375, 150) = 75.
The GCF is 15.