Answer:
The answer is 
Step-by-step explanation:
Exponential property of logarithm:
We have that:

Sum of logarithms:
We have that:

Applying the exponential property:


So

Additive property

Exponential property:

The answer is 
So (a) stands for adult and (c) is for child.
10a+5c=1200(total cost)
a+c=170(for tickets sold)
There are 70 adult tickets and 100 child tickets.
The mode is the value that appears more frequently. In this case, the mode is number 1.