Each person will receive 1/25 of a pot of coffee.
To find this you divide the fraction 1/5 by 5. When dividing a fraction by a whole number, you put the whole number over 1, flip the numerator and denominator (making it the inverse), then multiply the 2 fractions. So, instead of 1/5 divided by 5, you now have 1/5 times 1/5. Multiply straight across, 1 times 1 is one, and 5 times 5 is 25. Thus making the fraction 1/25.
I hope this helps!