After 40 minutes, Ralph has already painted (40/60)/12=1/18 of the fence
Lisa's speed is 1/15 fence/hour, Ralph's speed is 1/12 fence/hour, hence when they help each other their combined speed is 1/15+1/12=3/20
Thus we need to solve 3/20*x=17/18 thus x=170/27 hours (approx 6 hours 15 mins)
If nth means ninth then the answer is 15. If nth is not ninth then tell me I am glad to help!
Answer:

Step-by-step explanation:
Point slope form is: 

We are given the slope of
and the point of (8,4).
Replace 'm' with -5/6, 'x1' with 8, and 'y1' with 4.

I do not see any options that match this, but the boxed equation should the correct answer.
Let the unknown number be "n",
This number is sutracted from 46. So, 46 less n.
That is (46 - n).
The result to this is -21.
∴The equation would be;
46 - n = -21.
Now solve for n.
46-n=-21
46 + 21 =n
∴n=67