SOLUTION: 30 labours construct 15 rooms in 18 days . in how many days can 12 labourers construct 12 rooms of the same size

Algebra ->  Rate-of-work-word-problems -> SOLUTION: 30 labours construct 15 rooms in 18 days . in how many days can 12 labourers construct 12 rooms of the same size      Log On


   

Question 1032755: 30 labours construct 15 rooms in 18 days . in how many days can 12 labourers construct 12 rooms of the same size
Found 2 solutions by josgarithmetic, 2356:
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
r , the rate for 1 laborer.
30r, the rate of 30 laborers.
30r%2A18=15

The form for the rule would be nR%2At=j and the variables have meanings:
n   number of laborers
r   rate for 1 laborer
t   time of doing any amount of work to produce so much quantity of jobs
j   quantity of jobs

--
12%28r%29%2At=12

12%28%2815%29%2F%2830%2A18%29%29t=12
%281%2F36%29t=1
t=%2836%2F1%29
highlight%28t=36%29days

Answer by 2356(1) About Me  (Show Source):
You can put this solution on YOUR website!
this question can be solved through ratio and proportion so
Labours rooms Days
30 15 18
12 12 x
Days and labours have inverse proportion and days and rooms have direct proportion. so

(30/12) x (12/15) = x/18
2.5 x 0.8 = x/18
2 = x/18
x = 18 x 2
x = 36 days