When red and white snapdragon flowers are crossed, the offspring are pink. If these pink flowers are crossed with white ones, what percent of the seeds produced are likely to develop into pink flowers?

50%

Explanation:

This is a case of incoplete dominance of the red allele over the white allele.

Let the red allele be R and the white allele be r.

RR x rr = All Rr, pink flower phenotype.

The pink flower plants are then crossed with white flower plants;

Rr x rr = Rr (pink), Rr (pink), rr (white) and rr (white).

50% or 1/2 of the offspring will be pink flowered while the remaining 50% or 1/2 will be white flowered.