Answer:
1.60 
Step-by-step explanation:
Assuming that this is a cylindrical pipe, the area can be determined by applying the formula for calculating the area of a circle.
i.e Area = 

So that,
for the inner part of the pipe,
r = 
= 
= 2.5 feet
Area of the inner part of the pipe = 

= 3.14 x 
= 19.625
Are of the inner part of the pipe is 19.63
.
Total diameter of the pipe = 5 + 0.2
= 5.2 feet
r = 
= 2.6 feet
Area of the pipe = 

= 3.14 x 
= 21.2264
Area of the pipe is 21.23
.
Thus the cross sectional area = Area of the pipe - Area of the inner part of the pipe
= 21.2264 - 19.625
= 1.6014
The cross sectional area of the cement pipe is 1.60
.
It would be f= 1.25n+6.25/n
0.176 can be re-written as;

On simplifying by dividing by 8 , this gives;

<span />
AX = B
1 -1 -1 x 0
0 -2 -1 y = -2
2 1 0 z -4
x
y = A^-1 B
z
x -1 1 1 0 6
y = 2 -2 -1 . 2 = -8
z -4 3 2 4 14