SOLUTION: 1. 20 men can do a piece of work in 30 days.After working for how many days should 5 men leave the work so that the entire work will be completed in 35 days? 2. 20 men can do a pi

Algebra ->  Rate-of-work-word-problems -> SOLUTION: 1. 20 men can do a piece of work in 30 days.After working for how many days should 5 men leave the work so that the entire work will be completed in 35 days? 2. 20 men can do a pi      Log On


   



Question 1001833: 1. 20 men can do a piece of work in 30 days.After working for how many days should 5 men leave the work so that the entire work will be completed in 35 days?
2. 20 men can do a piece of work in 24 days.After working for few days , 4 men are added the work was finished 3 days earlier.After how many days were 4 men added?

Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
Helping here for #2, and you should try to work through #1 yourself.

One man rate is r.
The first sentence gives 20r%2A24=1, for the 1 job to be done.
The second sentence uses an unknown amount of time, t, after which men are added (4 of them) to finish the job in 3 days. This work was split into two parts, this way:

highlight_green%2824r%2At%2B%2824%2B4%29r%2A3=1%29.
If all of this is well understood, then you can continue. The question asks for the value of t. The value for rate r will come from the equation from the first sentence.

System of equations if this is more comfortable to see,
system%2820r%2A24=1%2C24rt%2B28r%2A3=1%29