So, what is the total lenght of the pieces that wer cut off?
we multiply the lenght by the number:
4
*5=20+
=21
and we subtract this from the original pipe, that is
30
-21
we need to bring the two fractions to the same denominator (by multiplying the fraction art in the first by 3 and 4 the second):
30
-21
=9 
so the correct answer is D!
we multiply the lenght by the number:
4
and we subtract this from the original pipe, that is
30
we need to bring the two fractions to the same denominator (by multiplying the fraction art in the first by 3 and 4 the second):
30
so the correct answer is D!