Question

If a seed is planted, it has a 65% chance of growing into a healthy plant.

Answer 1

Chance of seed growing into healthy plant:  0.65

Chance of seed NOT growing into a healthy plant:  0.35

To answer this question, we will use the nCr button on the calculator.

In this situation, n = 8   and r = 1.

If 1 seed doesn't grow, then 7 seeds will grow. So will raise 0.65 to the 7th power and 0.35 to a power of 1

7 seeds grow, so we use the 7th power

1 seed doesn't grow, so we use power 1 :

So the answer is:

⁸C₁ × (chance of successful growth)⁷ x (chance of Unsuccessful growth)¹

= ⁸C₁ × 0.65⁷ × 0.35¹

= 0.137   (3sf)

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Answer:

Probability that exactly one seed doesn't grow is:

0.137