If the answer is D. the equation to represent the ages of students is: n + n+1 + n+2 = 45 it is showing that n is the age of one student and the other student has age one year more than the first one and third students has age of 2 years more than first student and one year greater than the second student. if we solve this equation for the value of n, we get; 3n + 3 = 45 3n = 45 -3 3n = 42 n = 14 so the age of one student is 14, second student 15 and third student 16 years. and if we add there ages, 14 + 15 + 16 = 45
