Step-by-step explanation:
first of all, something like
5 ft 6 in
is always actually a short form of an addition :
5 ft + 6 in
so,
(5 ft 6 in) × 4 = 5×4 ft + 6×4 in = 20 ft 24 in
but 1 ft = 12 in.
that means that the 24 in are actually 2 ft.
and so, the fully cleaned-up answer is
20 ft + 2 ft = 22 ft (0 in)
