The answer is 9 out of 16 offspring or 56.25 percent.
It is known that the in dihybrid cross (a cross between two different traits), the phenotypic ratio between the offspring, which parents are heterozygous, is 9:3:3:1.
R is an allele for round seeds, r is the allele for wrinkled seeds.
Y is the allele for yellow seeds, and y is the allele for green seeds.
It can be assumed the following:
9 - individuals with both dominant traits (RRYY) - plants with round and yellow seeds.
3 - individuals with the first dominant trait and the second recessive trait (RRyy) - plants with round and green seeds.
3 - individuals with the first recessive trait and the first recessive trait (rrYY) - plants with wrinkled and yellow seeds.
1 - individual with both recessive traits (rryy) - plants with wrinkled and green seeds.