Answer
a) 1/64
b) 1/64
c) 1/8
d) 1/32
Work Step by Step
This problem is much easier than it looks. For a hypothetical cross of AaxAa (what is happening in the problem with each independent gene), progeny will be 1/4AA: 1/2Aa: 1/4aa. So, for example, in a), homozygous dominant is 1/4 for any one gene and 1/4x1/4x1/4=1/64 for the three genes together.