Answer:
$150,000
Explanation:
Murray can use the section 121 exclusion that reduces his capital gains by $250,000 (it would have been $500,000 if he was married), because he owned the house for 35 years (ownership test) and lived there for the past two years (use test).
Murray's taxable capital gains = $400,000 - $250,0000 = $150,000