Answer: 11/20
Step-by-step explanation: Find the GCD (or HCF) of numerator and denominator
GCD of 55 and 100 is 5
Divide both the numerator and denominator by the GCD
55 ÷ 5
-----------
100 ÷ 5
Reduced fraction:
11
20
Therefore, 55/100 simplified to lowest terms is 11/20.