Question

20 masons build a wall in 30 days. how many days 10 masons will take to build 2 similar walls?

Answer 1

20 masons build a wall in 30 days ⇒ 20 masons do a work of W/30 each day

⇒ 1 mason do's a work of W/600 each day

⇒ 10 masons do a work of W/60 each day

⇒ 10 masons build one wall in 60 days

⇒ 10 masons build two walls in 120 days.