this is an image of the given problem

so for (a) (i) I used $\frac{x-\mu}{\sigma}=z

\frac{0.70-0.76}{0.06}=-1 = a

$ and $\frac{0.79-0.76}{0.06}=.5 = b$

(ii) $P(.70<X)$ z-table for $-1$ is $0.3413$ so $0.3413 + .500 = 0.8413$

$P(.70<X<.79)$ z-table for $.5$ is $0.1915$ so $0.3413+0.1915=0.5328$

will get to (b) later

hope so far is