Takeovers – BPP Text Page 307 Reorganisation and Takeovers

Hi Guys,
Just working through the F6 Text Bpp FA13 Page 307 Reorganisation and Takeovers

J Ltd acquired 20,000 shares in G Ltd in August 1990 (RPI 128.1) at a cost of £40,000. It acquired a further 5,000 shares in December 2006 (RPI 202.7) at a cost of £30,000.

In September 2013, G Ltd was taken over by K Plc and J Ltd received one ordinary share and two preference shares in K Plc for each one share held in G Ltd. Immediately following the takeover, the ordinary shares in K Plc were worth £4 per share and the preference shares in K Plc were worth £1 per share.

(a) Show the cost and indexed cost of the ordinary shares and the preference shares in Kplc.
(b) Calculate the gain arising if J sells 10,000 ordinary shares in K plc for £42000 in Feb 14 RPI 255.3

Book Answer

Share Pool Shares Cost Index Cost

8.90 Aquisition 20,000 £40,000 £40,000
12.06 Index rise
202.7-128.1 / 128.1 x£40000 £23,294
Aquisition 5000 £30,000 £30,000
25000 £70,000 £93,294

apportionment of cost to K plc shares
Shares MV Cost Indexed Cost
Ords x1 25,000 £100,000 £46667 £62196
Prefs x2 50,000 £ 50,000 £23,333 £ 31,098
75,000 £150,000 £70,000 £93294

Could someone explain where they get the cost £46667 and £233333
I thought i would just divide cost 70,000 by 75000 shares – 93p/share and then multiply by share no. – or is it something to do with the type of share??? stuck, brains gone numb, please help ty. working through this on my own.
I have listened to the Open Tuition Lecture for chapter 13 but this is still not making sense.