Matching shares help!!

LinziAAT

Hi I keep getting confused with matching shares for the FA 1985 pool!

I have this question...

Carol purchased and sold shares in ceeco ltd
10 Apr purchased 5000 for £15000
12 Jan sold 1800 for £4000
1 Feb purchased £6800 for 21080
31 Mar sold 10000 for £4000

a. Gain or loss o shares on 12 Jan 2015
b. Gain or loss on shares on 31 Mar 2015

I know a is 1580 loss but I am unsure why we use the Feb shares? Is it because we have matched them with the FA 1985 pool? When it gets to the FA pool I come to a barrier! Any help is appreciated!

For b I assume the cost should be 30500 can anyone explain/show how I get a 9500 gain?

Thanks!

MMG

5000 for £15000 - 10 Apr purchased
5000 for £15500- 12 Jan disposal (you have to add because you sold less shares than purchased/or you purchased more shares than you sold, 6800-1800=5000, and cost: 21080/6800x5000=15500

a. Proceed: 4000
cost: (5580)
loss 1580

how to get 5580?
£21080/6800x1800

next part, after disposal we've got:
10000 for £30500
(10000) for (£30500)- disposal

b. proceed £40000
cost: (30500)
Gain :9500

That is my way how to find solution