Explanation:
Given,
LP = 15, PR = 9
Point P lies on the line segment PR. It would mean that,
LP + PR = LR
⇒LR = 15 + 9
⇒ LR = 24
Hence, "LR = 24 because LP + PR = LR according to the Segment Addition Postulate, and 15 + 9 = 24 using substitution" is the correct option.