Let x represent the number of days the second voyage lasted. The number of days the first voyage lasted is then x+43. Since the two voyages combined lasted a total of1,003 days, the equation x+(x+43)=1,003 must hold. Combining like terms yields 2x+43=1,003, and solving for x gives x=480. Choice A is incorrect because 460+(460+43)=963, not 1,003 days. Choice C is incorrect because 520+(520+43)=1,083, not 1,003 days. Choice D is incorrect because 540+(540+43)=1,123, not 1,003 days.