Answer:
12 hours
Step-by-step explanation:
Let Theo's siste can paint a fence in x times
Given.
Theo can paint a fence three times as fast as his sister can. Working together, they can paint a fence in 9 hours.

Apply cross multiplication

Theo’s sister to paint the fence in 12 hours.
Malik can remain honest with his partner Samuel and respect his opinion.
(x + 9)(x + 12) = 0
Expanding the brackets, we get:
#16: Let's clear the fraction on the way to solving this inequality for x. By mult. the given inequality by 2, we'll get -2 (is greater than) x+4. We want x to be positive. So, leave it where it is. Subtract 4 from both sides of this inequality. We end up with -6 (is greater than) x, which is the same thing as x (is less than) -6. What would the graph of that simple inequality look like?
Graph it. (Hint: The graph is a straight dashed line, and you must shade one side of it, but not the other side.