Normal distribution with a mean of $28.3$ and a standard deviation of $0.77$. We know that $X$ is at least $27$, what is the probability that $X$ will be between $29$ and $40$. I have calculated $P(29 \leq X \leq40)$ to be $0.18165$ and $P(X \geq 27)$ to be $0.954323$ using $R$. I am uncertain how to proceed in finding the intersection of the two probabilities.
$$ P(29\le X\le40| X\ge27) = \frac{P(29\le X \le 40 \cap X \ge27)}{P(X \ge 27)} $$
If $ 29 \leq X \leq 40$, then $X \geq 27$, this means $P(29 \leq X \leq 40 \cap X \geq 27) = P(29 \leq X \leq 40)$.