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**IBDP** **Mathematics**** Question Analysis Topic: Mathematics - Probability**

**Exam Question: **

The probability of selecting a rotten apple randomly from a heap of 900 apples is 0.18. What is the number of rotten apple in the heap?

**Answer:**

For IBDP Mathematics, you should know:

Let A be the event that a rotten apple is selected.

Therefore, P(A) = 0.18

Total number of apples = 990 (given)

P(A) = n(A)/n(S),

therefore n(A) = 0.18 x 900

n(A) = 162

As such, there are 162 rotten apples in the heap.

Work hard for your IBDP Mathematics examination!

End of analysis. Great!