24.4 Compute the corporation tax liability of each of the following companies:

(a) For the year to 28 February 2009, Company X has chargeable profits of £875,983 and FII of £32,800.

(b) For the six months to 31 December 2009, Company Y has chargeable profits of

£200,000 and no FII.

(c) For the year to 31 March 2010, Company Z has chargeable profits of £428,000 and no FII.

For Company Z, recalculate the corporation tax liability if chargeable profits were lower by £100,000 and demonstrate that the company's marginal rate is 29.75%.