The total number of progeny obtained from a dihybrid cross is 1280 in the F2 generation. How many of them are recombinant ?

The phenotypic ratio of a typical mendelian dihybrid cross is 9:3:3:1. Where 3:3 is for recombinants. Therefore, if 1280 progenies are obtained in F2 generation then the number of recombinants will be equal to 1280×616=480.