I'm not 100% sure this is right but I think this is how you do it
Answer:
and

Step-by-step explanation:
Assume that Mike bought only cookies and hot dogs.
The total can be represented as:
--- (1)
And the amount spent can be represented as:
--- (2)
Required
Determine the system of equation
Let c represents the number of cookies and h, number of hot dogs.
implies 
And
Cost of cookies = 0.75 * c
Cost of hot dogs = 1.10 * h
So, we have:

Hence, the equations are:
and

Solving for c and h
Make c the subject in 

Substitute 5 - h for c in 



Collect Like Terms


Solve for h


-- approximated
Recall that:



Velocity of the car is equal to the distance travelled by the time spent.
If V= velocity, d = distance & time = t, then
the equation becomes V=d/t
Answer:
The second boat will catch up in 8.5 hours, and they will be 187 km from their port.
Step-by-step explanation:
Since the system of equations are d=18t+34 and d=22t, you first rewrite d=18t+34 as an equation. 18t+34=22 and that equals to 8.5=t. Then you solve the next one d=22t and the answer you got from the other equation, you substitute d=22(8.5) and that equals to 187.