Vemos que $X \longrightarrow N(150, 30)$
a) $P(X \leq 130) = P\left(Z \leq \frac130-15030\right)=P\left(Z \leq -0.67\right)= 1- P\left(Z \leq 0.67\right)=1- 0.7486=0.2514$
b) $P(X \geq 190) = P\left(Z \geq \frac190-15030\right)=P\left(Z \geq 1.33\right)= 1- P\left(Z \leq 1.33\right)=1- (…)