Answer :
16 walls in 40 hours
3 walls in h hours
16/40 = 3/h
16h = 40(3)
16h = 120
h=120/16
h=7.5
answer: 3 walls in 7.5 hours
3 walls in h hours
16/40 = 3/h
16h = 40(3)
16h = 120
h=120/16
h=7.5
answer: 3 walls in 7.5 hours