Investment at cost for Goodwill calculation

Extracts from the trial balance of Subsidery show share capital of $100,000 consisting of
ordinary shares of $0.50 each. Of these Pull bought 150,000 shares on 1
September 2014, for the sum of $400,000 when the reserves stood at $200,000
and the fair value of its shares was $1 each.

Given this information, I tried to work out the investment at cost of CI and NCI. But that is me trying this question is for consolidated statement of profit and loss, not sure if the givens are enough.

investment at cost
CI $400,000
NCI $50,000 (50,000 shares $1 each fair value)
I used the fair value of the share for the NCI part.

I am asking you if my figure of NCI is correct, if so how the NCI can get the benefit to buy the share of subsidiary at price lower than what CI paid and share the GW on their percentage.

thank you very much Sir