Premise: The 15th BRDC International Trophy was a motor race, run to Formula One rules, held on 11 May 1963 at the Silverstone Circuit, England. The race was run over 52 laps of the Silverstone Grand Prix circuit, and was won by British driver Jim Clark in a Lotus 25.
Hypothesis: The 15th BRDC International Trophy race was 26 + 26 laps of the Silverstone Grand Prix Circuit.