Concept:Forming a linear equation from the given relationship between two ages.Solution:Let Araba's age be x years.Since Araba is 3 years younger than her sister, her sister's age is x+3 years.The sum of their ages is 17 years.So, x+(x+3)=17Combine like terms: 2x+3=17Subtract 3 from both sides: 2x=14Divide both sides by 2: x=7Answer:Option A (7 years)