Its all up to you and how hard you are willing to work to get that may credits in one semester. But you could do it. Hope that helped!
length of pipe= 30m
Inside dia. = 1.2m
Outside dia. = 1.8m
Volume of concrete= (outside dia. - inside dia.)h
V= (pi)
v= [(3.14*0.9*0.9)-(3.14*0.6*0.6)]30
v= (3.3534-1.1304)30
v=(2.233)30 = 66.690m cube
since it's volume the answer 66.690 is in cubic meters.
This is all percentages so...
4/9 = 44%
2/7 = 29%
1/10 = 10%
Total = 83%
So 17% of 630 is left over which = 107
Well I can’t see where x would be therefore I can’t tell you how to get to x