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.
Answer: 84,300,000
Simply move the decimal place to the right 7 places
Let's solve for x.<span><span><span>3x</span>−<span>4y</span></span>=3</span>Step 1: Add 4y to both sides.<span><span><span><span>3x</span>−<span>4y</span></span>+<span>4y</span></span>=<span>3+<span>4y</span></span></span><span><span>3x</span>=<span><span>4y</span>+3</span></span>Step 2: Divide both sides by 3.<span><span><span>3x</span>3</span>=<span><span><span>4y</span>+3</span>3</span></span><span>x=<span><span><span>43</span>y</span>+1</span></span>Answer:<span>x=<span><span><span>43</span>y</span>+<span>1</span></span></span>
6.2 I belive.................................