Question

One bricklayer can build a wall in 6 hours. Another bricklayer could build the same wall in 4 hours. If they work together, how long will it take to build the wall?

a5 hours b2.4 hours c10 hours d2 hours

Answer 1

1 wall 1 1 24
----------------------------- = ------------------- = ---------------- = ------- = 12/5 hour, or
1 wall 1 wall 1/6 + 1/4 4 6 10
----------- + ------------ ----- + ---- 2 hr 24 min
6 hrs 4 hrs 24 24 (answer)