Answer:
Riley divided the number of petunia seeds by the number of begonia seeds, getting [tex]\frac {5}{15} = \frac {1}{3}[/tex]. What you actually need to do to calculate the probability of selecting a petunia seed is divide the number of petunia seeds by the total number of seeds. 5 petunia seeds and 15 begonia seeds makes 20 total seeds, so you divide 5 petunia seeds by 20 total seeds to get [tex]\frac {5}{20} = \frac {1}{4}[/tex].
