find how long it takes if they work together?
2006-11-11 21:50:45 · 9 answers · asked by ahelp 1 in Science & Mathematics ➔ Mathematics
2 hours
edit: WHY would it be more than 3 hours??? if the brickie does it alone it would be 3 hours max. why say 4.5 hours?? :(
2006-11-11 21:52:39 · answer #1 · answered by Spike2012 2 · 0⤊ 0⤋
The speed of construction of the apprentice is half that of the experienced man. So, we can say that a team (apprentice +experienced) are worth 1.5 experienced man. Since eperienced bricklayer takes 3 hours , 1.5 experienced would take 3/1.5 =2 hours
2006-11-12 06:08:25 · answer #2 · answered by maussy 7 · 0⤊ 0⤋
Mathematically it would take 4 1/2 hrs. Because, the bricklayer is taking time to teach the apprentice.
2006-11-12 06:04:52 · answer #3 · answered by Anonymous · 0⤊ 0⤋
the brecklayer does 1/3 rd of total in 1 hr
the apprentice does 1/6 th of total in 1 hr
so they do (1/3)+(1/6) = 1/2 in one hr
so they complete it in 2 hrs
2006-11-12 05:54:47 · answer #4 · answered by Pramita 1 · 0⤊ 0⤋
2 hours
The experienced brick layer (EBL) works twice as fast as the apprentice (A) so, when they are working together, he will build twice as much wall as the apprentice. The EBL will build two thirds of the wall while the A builds one third.
If the EBL builds a whole wall in three hours he can build two thirds of one in two hours
2006-11-12 06:03:00 · answer #5 · answered by Calum 1 · 0⤊ 0⤋
4 hours and 30 minutes
2006-11-12 05:52:42 · answer #6 · answered by morningstar 3 · 0⤊ 0⤋
4 and a half hours
2006-11-12 05:53:23 · answer #7 · answered by sharkgirl 7 · 0⤊ 0⤋
x/3+x/6=1
2x/6+x/6=1
2x+x=6
3x=6
x=2 hrs.
2006-11-12 05:54:17 · answer #8 · answered by Steph_kinse 2 · 0⤊ 0⤋
J/R = 3
J/r = 6
R = J/3
r = J/6
J/(R + r) = J/(J/3 + J/6) = J/ (2J/6 + J/6) = J/(3J/6) =
6J/3J = 2 hr
2006-11-12 06:09:14 · answer #9 · answered by Helmut 7 · 0⤊ 0⤋