20.4 Samantha bought a house for £37,500 on 1 August 1988 and occupied the house as her principal private residence. On 1 June 1990 she began to use one-fifth of the house for business purposes. Unfortunately her business eventually failed and on 1 June 1997 she ceased trading. From that date onwards she resided in the entire house until it was sold on 1 August 2009 for £155,000. Compute the chargeable gain.