QUESTION $4$

a$)$ If a and $b$ are elements of the set Person, then we write a childOf $b$ to indicate that $a$

is a child of $b.$

Each person has exactly two genetic parents, one drawn from the set Male and the other

from the set Female $-$ these are disjoint sets such that

Person $=$ Male $$ Female

Using the definitions above, give suitable expressions for the following.

i$)$ The relation fatherOf, which holds between two people exactly when the first is the

male parent of the second.

ii$)$ The relation siblingOf, which holds between two people exactly when the first is

either a brother or a sister of the second.

iii$)$ The relation cousinOf, which holds between two people exactly when the first is a

cousin of the second.

b$)$ You are going to cook a meal of mashed potato, onion and broccoli frittata, and peas. You

identify the following jobs and estimate their durations:

i$)$ Define the precedence relation of these activities.

ii$)$ Draw the activity network for cooking the meal.

iii$)$ Calculate the critical path for cooking the meal.