Question $4$

Mr$.$ K$\text{'}$s is a very popular hair salon. It 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 homemade herb tea. $(10$ minutes$)$

Activity $2$: Wash and condition hair. $(10$ minutes$)$

Activity $3$: Neck, shoulder, and back stress release massage. $(10$ minutes$)$

Activity $4$: Design the hair style and do the hair. $(30$ minutes$)$

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

Three servers $($S$1,$ S$2,$ and S$3)$ offer the services in a worker$-$paced line. The assignment of tasks to servers is the following:

S$1$ does Activity $1.$

S$2$ does Activities $2$ and Activity $3.$

S$3$ does Activities $4$ and Activity $5.$

Assume a wage rate of $$10$ per hour. What are the direct labor costs $($in $ $)$ for one guest? $($The accuracy should be of two digits after

the decimal places.$)$