$2.$ Mr$.$ K$$s Other Hair Salon $(30$ points$)$

Mr$.$ K also has a second hair salon. Similar to last week, this salon also offers high$-$quality

hair$-$styling and physical relaxation services at a reasonable price, so it always has unlimited

demand. The service process includes five activities that are conducted in the sequence

described below. $($The time required for each activity is shown in parenthesis$)$:

Activity $1$: Welcome a guest and offer a cup of coffee. $(5$ minutes$)$

Activity $2$: Neck, shoulder, and back stress release massage. $(15$ minutes$)$

Activity $3$: Design the hairstyle and do the hair. $(30$ minutes$)$

Activity $4$: Wash and condition hair. $(10$ minutes$)$

Activity $5$: Check out the guest. $(5$ minutes$)$