Final answer:
The value of t is found by setting up and solving the equation 2t + t = t + 30, which simplifies to 3t = t + 30. The correct value for t is 15.
Step-by-step explanation:
The student is trying to figure out the value of t in the context of a geometric problem, where the lengths of line segments DE, EF, FG, and DG are related algebraically. Given the equations DE = 2t, EF = FG, and DG = t + 30, we can find t by setting up an equation.
Since EF = FG and DE + EF = DG, then DE + FG = DG. Substituting the given values, we have 2t + (t) = t + 30. By simplifying this equation, we get 2t + t = t + 30 which reduces to 3t = t + 30.
Solving for t:
3t - t = 30
t = 15
Therefore, the correct answer is B. t = 15.