Answer:

What is given to you is interval notation. We have the interval start at 0 and end at 8. The value 0 is not included in the interval as indicated by the parenthesis. So we go with a "less than" sign (instead of a "less than or equal to" sign)
The value 8 is included since a square bracket is used here. The use of "or equal to" is needed to make sure the endpoint 8 is included.
So x can be any number between 0 and 8. It can't be 0 but it can be 8.
I'm not 100% sur what it is asking but I think the expression would be
15 min. * 10 = min. till the tank is full
Answer: 
Step-by-step explanation:
Corresponding sides of similar triangles are proportional, so:

171.76 ÷ 555 = 0.3094774775