6%. Further crosses are needed involving: 1) red eye-gray body (heterozygous for both) x white eye black body (homozygous for both); 2) red eye normal wing (heterozygous for both) x white eye vestigial wing (homozygous for both).
Work Step by Step
To get the recombination frequency, find the percentage represented by the recombinants (49, 45) of the whole (add up all flies scored). The other needed crosses simply involve all other combinations among the three genes being mapped between a heterozygous individual and a homozygous recessive individual.