I think that the best answer is A
For every second the water runs it rises 15 mm and the slope of the graph is 15.
The answer would be 390+ 390 =780
ANSWER
EXPLANATION
Note that the expression which comes immediately after from comes first.
We convert the minus minus to plus
We expand to obtain,
We group like terms to obtain,
We simplify to obtain,
Someone told me if I answer a question I can watch videos to unlock my answer sorry