Well we know that:
Volume = l×w×h
so that means:
40 = l×w×h
Well if the length is doubled that means
New Volume = 2l×w×h or
New Volume = 2×l×w×h
Well since we know from our original equation that 40 = l×w×h, we can substitute it into this new volume equation
New Volume = 2×l×w×h
New Volume = 2×(40)
New volume = 80 cm³
