Penn-Foster Civil exam question help

ok guys can some one explain the math so I can try to figure this out. page 19 in the Civil drafting book study unit. Thanks everyone

sorry uploaded it twice. here is the other question

The math is simple proportion.

Understanding what information you are given is another problem.

Well for starters "IE" (which should have been spelled out) stands for invert elevation. That's the elevation of the pipe entering/leaving the manhole.

Sta. = station. Stationing usually starts at 0+00.00. Manhole #1 is at station 1+59.11 which is 159.11' (from station 0+00). Manhole #2 is at station 3+07.09 which is 307.09' (from station 0+00).

For your first problem divide the difference in elevation of the two inverts by the distance between the two manholes then multiple that number by 100 to get the percent grade (slope). Can you do that?

In the second problem you have been given the slope (or percent grade) and are asked to calculate the invert elevation of a pipe. Kind of the reverse of what you were asked to do in problem 1.

Do you have to use a calculator?

It is easier to draw out, and you can see sense in the figures.

Use the stationing along the x axis and the elevation along the y axis.

Ok ill work on it when i get back home from work. Thanks guys

Re: second problem.

Calculate the overall distance between the two manholes. Multiple that by the slope then subtract what you get from the invert elevation of 115.76 to arrive at the answer.

im going to do it from work boss not here today. ha ha ill post answer

Next step of the home work you now have the start and end info but need to draw the pipe but Horizontal & vert scales come into play or is that the next question ?

Remark and eldon,

here is what I got

307.09 - 159.11= 147.98

248.33 - 234.58= 13.75

147.98 Divided by 13.75 = 10.7621818182 X 100 =1,076.21

not sure what the answer is here.

Big Al this is the Examination part of the Civil Drafting. I started the drawing and thought it be better to read and take the test first.

i played with the numbers and its 13.75 divided by 147.98 = 9.29 so the answer to Q1 is C 9.29%

I sympathize with your "playing" with numbers, but you should know the reason for the answer.

A slope grade percent is "Rise (vertical distance) divided by Run (Horizontal distance)" times 100 (for percentage)

That's why we are called students. see know I know how to do it. Thank you and remark for help.