Given :
The decimal number = 0.0155
Write it as a fraction = 0.0155 / 1
Multiply 10000 to both numerator & denominator
(0.0155 x 10000)/(1 x 10000) = 155/10000

It can be written as 1.55% = 1.55/100 or 155/10000
To simplify 155/10000 to its lowest terms, find LCM (Least Common Multiple) for 155 & 10000.
5 is the LCM for 155 & 10000

Divide numerator & denominator by 5
155/10000 = (155 / 5) / (10000 / 5)
= 31/2000
31/2000 is a simplest fraction for the decimal point number 0.0155