to simplify the given fraction
we have to divide both numerator and denominator by the highest common factor
the factors for both 15 and 100 are as follows
15 - 1, 3, 5, 15
100 - 1, 2, 4, 5, 10, 20, 25, 50, 100
from the factors given for both 15 and 100, the highest factor common for both is 5.
therefore we have to divide both numerator and denominator by 5

the simplest form for the fraction is 