Answer:
12%
Explanation:
The genes E/e and F/f are 24 cM apart.
A distance of 24 cM means that the frequency of recombination between the two genes is 24%.
The cross Ef/eF x ef/ef would produce the following offspring:
The total percentage of recombinant gametes is 24%, and there are two possible recombinant gametes, so each of them appears in 12% of the cases.
The individuals with elongated wings and five stripes have the recombinant genotype EF/ef, therefore the percentage of the offspring with this phenotype is 12%.