Can some one explain the difference between phenotype ratio and genotype ratios?

Question

anonymous · Answer

A genotypic ratio is the fraction of individuals who are likely display various genotypes in a cross. A phenotypic ratio isthe fraction of individuals likely to display various phenotypes in a cross.

aaronq · Answer

a ratio is a fraction, if you have 3 bananas and 6 apples, you have 1:2 bananas to apples.

Genotype = what genes (alleles) they have

Phenotype = what they look like (e.g. black coloured)

if you have 4 individuals and the 2 have BB, one has Bb and another bb.

Assuming that B is dominant over b, where BB and Bb are black but bb is white, 

then your genotypic ratio is BB:Bb:bb, 2:1:1 

but your phenotypic ratio is Black:white, 3:1