Note that angle ACD = angle BCE. thus, $\displaystyle \angle ACD + \angle BCE + \angle ACB = 180$

$\displaystyle \Rightarrow 2 \angle ACD + \angle ACB = 180$

$\displaystyle \Rightarrow \angle ACD = \frac {180 - \angle ACB}2$

now you can find $\displaystyle \angle ACB$, right (hint: the triangle is isosceles). thus you will find $\displaystyle \angle ACD$

Quote:

2. If 10 men take 6 days to lay 1000 bricks, how many days will it take 20 men to lay 5000 bricks?

I know the answer is 15 days. Just need help setting the equation up. TY

intuitive approach:

if it takes 10 men 6 days to make 1000 bricks, it will take them 5 times as long to make 5000 bricks, that is, it takes 10 men 30 days to make 5000 bricks. thus, if you double the men, you cut the time in half, and hence, it takes 20 men 30/2 = 15 days to make 5000 bricks