SOLUTION: 16 men can finish a work in 12 days. After they worked for 4 days, some more men joined them and they together completed the remaining work in 4 days. How many more men joined in

Algebra ->  Rate-of-work-word-problems -> SOLUTION: 16 men can finish a work in 12 days. After they worked for 4 days, some more men joined them and they together completed the remaining work in 4 days. How many more men joined in      Log On


   

Question 986070: 16 men can finish a work in 12 days. After they worked for 4 days, some more men joined them and they together completed the remaining work in 4 days. How many more men joined in ?
Found 2 solutions by ikleyn, josgarithmetic:
Answer by ikleyn(52835) About Me  (Show Source):
You can put this solution on YOUR website!
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16 men joined in.


Answer by josgarithmetic(39623) About Me  (Show Source):
You can put this solution on YOUR website!
r, rate of one man in JOBS per DAY;
n, unknown number of men WHO JOINED IN, after the four days;

system%2816r%2A12=1%2C16r%2A4%2B%2816%2Bn%29r%2A4=1%29

system%2816%2A12r=1%2C16%2A4%2Ar%2B16%2A4%2Ar%2B4nr=1%29

system%28highlight_green%28r=1%2F%2816%2A12%29%29%2C2%2A16%2A4%2Ar%2B16%2A4%2Ar%2An=1%29

16%2A4nr=1-2%2A16%2A4%2Ar

n=%281-2%2A16%2A4%2Ar%29%2F%2816%2A4%2Ar%29

n=%281-2%2A16%2A4%2Ar%29%2F%2816%2A4%2Ar%29

n=%281-2%2A16%2A4%2A%281%2F%2816%2A12%29%29%29%2F%2816%2A4%2A%281%2F%2816%2A12%29%29%29

n=%281-2%2A%281%2F3%29%29%2F%281%2F3%29

n=%28%281-2%2A%281%2F3%29%29%2F%281%2F3%29%29%283%2F3%29

n=%283-2%29%2F1

highlight%28n=1%29