Answer: 
Step-by-step explanation:
You must draw a right triangle as the one attached, where "x" is the lenght in feet of the ramp.
You need to use the following Trigonometric Identity:

In this case you can identify that:

Now you must substitute these values into
:

Finally, you must solve for "x" in order to find its value.
This is:

2x -20 -1 =0
2x -21=0
2x=21
x= 10.5
The answer, at least what I got, is 17.375 . They'd have to open an eighteenth package because the extra .375 is not in the original package, so I would go with B .
Part a I am pretty sure it is a pattern so 4 plus 2 is 6, 6 plus 3 is nine and then 9 plus 4 is 13 Then 13 plus 5 is 18
Answer is 18
In part b he will not finish his work he has to get to 274 and he only gets to about 50 something
Hope this helps
1+2 equals three i used a calculator