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

Hint: The probability of any event happening is given by dividing the number of outcomes of that event divided by the total number of events, that is;
$P = \dfrac{{{\text{Number of favourable outcomes}}}}{{{\text{Total number of outcomes}}}}$
Apply this formula, and then use the given conditions to find the required value.


Complete step-by-step solution
Let us carefully read the given question and observe that it says that the total number of apples are 900.
Thus, in this case we get that our total number of outcomes are 900.

Let the number of outcomes of selecting a rotten apple randomly from a leap of 900 apples be $x$.

We use the formula of probability given by, $P = \dfrac{{{\text{Number of favourable outcomes}}}}{{{\text{Total number of outcomes}}}}$ and substitute the obtained values in it.
$P = \dfrac{x}{{900}}$

Now, we use the fact given in the question that the probability of selecting a rotten apple randomly from a heap of 900 apples is 0.18.

Thus, we get,
$
  0.18 = \dfrac{x}{{900}} \\
   \Rightarrow x = 162 \\
$

Thus, the number of rotten apples in the heap is 162.

Note: In solving these types of questions, you should be familiar with the formula to find the probability of any event happening. Then use the given conditions and values given in the question, and substitute in the formula for probability of the event, to find the missing values.
Avoid any calculation mistakes.