f6 Practice 13. Stephen

13 Stephen
£
2008/09 Actual 1/2/2009 – 5/4/2009 (30,000 × 2/15) 4,000
2009/10 Actual 6/4/2009 – 5/4/2010 (30,000 × 12/15) 24,000
2010/11 12 months to accounting date ended in tax year 12m to 30/4/2010 (30,000 × 12/15) 24,000
2011/12 CYB Y/e 30/4/2011 10,000
2012/13 CYB Y/e 30/4/2012 12,000
2013/14 CYB Y/e 30/4/2013 15,000
2014/15 Y/e 30/4/2014 18,000
P/e 31/10/2014 7,000
Less: Overlap 25,000
1/5/2009 – 5/4/2010 (11/15 × 30,000) (22,000)
3,000

How the overlap profits are calculated as 22000?? i thought it was 10/12 of 24000=20000. what is my mistake sir??