Consider the following security information for four securities making up an index. What is the change in the value of the index from t = 0 to t = 1 if the index is calculated using a value-weighted arithmetic mean?

Security 1 2 3 4 Price t=0 8 22 35 50 Price t=1 13 25 30 55 Shares Outstanding (millions) 20 50 120 75