work prob.

[tRNA]

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spent 30min on this one, still don't get it, answer is 1and 2/3 months plz explain how???
thanks

 

[Ex_EE]

Here is the situation:
25 workers it takes 5 months
15 workers at 5/6 the rate take 10 months
so work per month they can accomplish together is
1/5+1/10=1/t so, t = 3.33 which is time it takes to get the whole job done. This is 1 2/3 months faster.
Check out this website for more help with problems like this.
http://www.purplemath.com/modules/workprob.htm

 

[Ex_EE]

duplicate post.

 

[tRNA]

how did u get 10 months?
if the rate of 25 workers is 5 months, 5/6 of 5 months is not 10 months

 

[Streetwolf]

how did u get 10 months?
if the rate of 25 workers is 5 months, 5/6 of 5 months is not 10 months

25 workers take 5 months.

15 workers is 3/5 the amount of workers so they take 5/3 the amount of time if they work at the same rate = 25/3 months. But they only work at 5/6 the rate so it will take them 6/5 the amount of time.

25/3 months * 6/5 = 10 months.

 

[JamieMac]

how did u get 10 months?
if the rate of 25 workers is 5 months, 5/6 of 5 months is not 10 months

OR... 15 workers working at 5/6 the rate the normal crew would be = to 12.5 members of a normal crew. Since it takes 25 normal crew 5 months, it would take 1/2 of them 10 months to complete.