If a plant with red flowers is crossed with a plant with white flowers and the resulting offspring have pink flowers, this is incomplete dominance. So the red flowered plant is RR and the white flowered plant is rr and the pink plant is Rr. If two pink flowered plants are crossed, that is RrxRr. The resulting offspring are: 1:RR, 2: Rr, 1: rr. There are 1/4 or 25% white flowered plants.