Answer:
100%, 50%
Explanation:
A testcross involves crossing an organism of unknown zygosity with its homozygous recessive version.
Assuming the purple flower pea plant is homozygous for the trait with genotype PP and it is crossed with homozygous recessive pea plant pp.
PP x pp = Pp, Pp, Pp, and Pp
100% of the progeny will be purple in appearance.
On the other hand, assuming the purple flower pea plant is heterozygous with genotype Pp and this is testcrossed with a pp plant.
Pp x pp = Pp, Pp, pp, and pp
50% of the progeny will be purple and the remaining 50% will be white.
Hence, If you were to perform a test-cross to determine the genotype of a purple-flowered plant, you would expect the percentage of purple-flowered progeny to be 100% if the plant is homozygous and 50% if the plant is heterozygous.