Answer:
25
Step-by-step explanation:
Find factors of:
25: 1, 5, 25
50: 1, 2, 5, 10, 25, 50
100: 1, 2, 4, 5, 10, 20, 25, 50, 100
Reduce possibilities to only common factors
25: 1, 5, 25
50: 1, 5, 25
100: 1, 5, 25
The greatest of these factors is 25
Greatest Common Factor (GCF) = 25
Hope this helps :)