Question

A bowl of flower seeds contains 5 petunia seeds and 15 begonia seeds. Riley calculated the probability that a random selected seed is a petunia seed as 1/3. Describe and correct Riley's error.​

Answer 1

Riley divided the number of petunia seeds by the number of begonia seeds, getting
`\frac {5}{15} = \frac {1}{3}`. 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
`\frac {5}{20} = \frac {1}{4}`.