Study the following information and answer the question given below:
A family has 5 members P, Q, R, S and T. each have a different weight.
i. P weighs twice as much as Q
ii. Q weighs four and a half times as much as R
iii. R weighs half as much as S
iv. S weighs half as much as T
v. T weighs less than P but more than R
Which of the following member of a family is the lightest in weight?