Answer:
100%
Explanation:
This question involves a single gene coding for flower color in pea plants. The allele for purple flowers (P) are dominant to white flowers (p). This means that purple color will be expressed in a heterozygous state.
According to this question, If two white flowered plants are cross i.e. pp × pp, the following gametes will be produced by each of the parent: p and p. Using these gametes in a punnet square (see attached image), ALL (100%) of the offsprings will be white colored (pp).
Therefore, 100% of the offsprings will be white flowered.