A pea plant is the offspring of a true breeding plant with purple flowers and a true breeding plant with white flowers. This plant is crossed with one that has white flowers(recessive). How many of the plants in the next generation will have white flowers

using the punnett square

Explanation:

                     P   P  true breeding

                  p Pp Pp

                  p Pp Pp               Mix Gen

                                             P     p

                                         p  Pp  pp

                                         p  pp  pp

So three out of the four have white flowers