A cross is performed between a plant with genotype TtYy and a plant with genotype Ttyy. If the two genes independently assort, what is the probability, expressed as a decimal, that the offspring will be homozygous for gene T?

As you can see in the table provided below when you do a punnet's square for the given genotypes, you get the possible genotypes of their offspring.

Marked in blue are the genotypes homozygous for gene T.

There are 4 out of 16 of them or expressed as a decimal 0,25.