# Ex.15.1 Q5 Probability Solution - NCERT Maths Class 10

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## Question

If \(\begin{align}{P(E)} = 0.05,\end{align}\) what is the probability of 'not \({}E\)?

## Text Solution

**What is known?**

\(P(E) = 0.05\)

**What is unknown?**

Probability of ‘not E’

**Reasoning:**

Probability of not happening an event is equal to \(1\) minus probability of happening an event.

**Steps:**

\[\begin{align} {P}({E}) &=0.05\end{align}\]

We know that

\[\begin{align} {P}\,({E})+{P}\,(\text { not } {E}) &=1 \\ 0.05+{P} (\text { not }E) &=1 \\ {P}\,(\text { not } {E}) &=1-0.05 \\ {P}\,(\text { not }E) &=0.95 \end{align}\]

Thus the probability of 'not \({E}\)' is \(0.95.\)