Answer:
5.83 cubic feet
Step-by-step explanation:
Volume of block1 :
l = 4 ft
[tex]\sf w = \dfrac{5}{6} \ ft\\\\ h = 1\dfrac{1}{6}=\dfrac{7}{6} \ ft[/tex]
[tex]\sf Volume \ of \ block1 = l*w*h\\[/tex]
[tex]\sf =4 *\dfrac{5}{6}*\dfrac{7}{6}\\\\ =\dfrac{5}{3}*\dfrac{7}{3}\\\\= \dfrac{35}{9} \ cubicfeet[/tex]
Volume of block2:
l = 4 ft
[tex]w = 1\dfrac{2}{3}-\dfrac{5}{6}\\\\ =\dfrac{5}{3}-\dfrac{5}{6}\\\\ =\dfrac{5*2}{3*2}-\dfrac{5}{6}\\\\=\dfrac{10}{6}-\dfrac{5}{6}\\\\w =\dfrac{5}{6} \ ft\\\\h =\dfrac{7}{12} \ ft[/tex]
[tex]\sf Volume \ of \ block2 = 4 *\dfrac{5}{6}*\dfrac{7}{12}[/tex]
[tex]\sf = \dfrac{5}{6}*\dfrac{7}{3}\\\\= \dfrac{35}{18} \ cubicft[/tex]
Amount of concrete to build stairs = Volume of block1 + volume of block2
[tex]\sf = \dfrac{35}{9}+\dfrac{35}{18}\\\\=\dfrac{35*2}{9*2}+\dfrac{35}{18}\\\\=\dfrac{70}{18}+\dfrac{35}{18}\\\\=\dfrac{105}{18}\\\\= 5.83 \ cubic feet[/tex]
