Answer: Heather served 15 orders, Kareem served 20 orders, and Chris served 30 orders.
Step-by-step explanation: Let H be the number of orders that Heather served, K be the number of orders that Kareem served, and C be the number of orders that Chris served.
We are given that C = 2*H and K = H + 5.
We are also given that H + K + C = 81.
Substituting the expressions for C and K into the equation, we get:
H + (H + 5) + (2*H) = 81
5*H + 5 = 81
5*H = 76
H = 15
Since Heather served 15 orders, Kareem served 15 + 5 = 20 orders and Chris served 2*15 = 30 orders.
Therefore, Heather served 15 orders, Kareem served 20 orders, and Chris served 30 orders.