Answer:
You need to do the Punnet square. If you cross a Homogeneous Red plant, RR, crossed with a Homogeneous white plant, WW, you will get 1 outcome. Through the Punnet square you find out that you get all R.W in your first generation, R.W. being your pink co-dominant plant offspring. In the second generation, you Cross 2 of the Heterogeneous offspring R.W x R.W and get the 1:1:2 ratio of red : white : pink respectively.