20 workmen can make 35 widgets in 5 days. How many workmen are needed

Question

20 workmen can make 35 widgets in 5 days. How many workmen are needed to make 105 widgets in 5 days?

(A) 7
(B) 20
(C) 25
(D) 30
(E) 60

GMATinsight · Accepted Answer

CONCEPT :  \frac{(Machine_Power * Time)}{Work} = Constant   
i.e.  \frac{(M_1 * T_1)}{W_1} = \frac{(M_2 * T_2)}{W_2}

i.e.  \frac{(20 * 5)}{35} = \frac{(M_2 * 5)}{105}

i.e.  M_2 = 60

Answer: option E

Sangeeta2018 · Answer

35w--------5days------20Men
1w----------5days------20/35Men
1w----------1day---------(20/35)*5 Men
105w-------1day--------(20/35)*5*105Men
105w-------5days-------(20/35)*5*105*1/5 Men
Ans=60 Men

sashiim20 · Answer

20  workmen can make  35  widgets in  5  days.

Let the number of workmen to make  105  widgets in  5  days be  = x

Number of days ie;  5  is same in both cases, hence we can ignore that.

\frac{20}{35} = \frac{x}{105}

x = \frac{20*105}{35} = 60

Hence  60  men are required to make  105  widgets in  5  days.
 
Answer (E)...

generis · Answer

W = # * r * t, where # = number of workers. Manipulate that equation in same way as W = rt.

Individual worker's rate is 35/(5*20), or 35/100, or  \frac{7}{20}

New # of workers, using individual rate, is 105/ , or 105/(35/20), or 105/(7/4) =

105 *  \frac{4}{7}  = 60

Answer E

gracie · Answer

let w=workmen needed
because time is equal,
w/20=105/35
w=60 workmen
E

Mo2men · Answer

This problem could be solved conceptually without calculations

We have 20 worker to produce 35 widgtes in 5 days. In same number of days, we need more worker to produce Three TIMES (105/35 =3) the first situation. So we need 3 Times labor.

Answer: 60

TimeTraveller · Answer

The output has increased but not the number of days, so the number of men should increase linearly.

Since the output has become thrice, the number of men required will be = 20*3 = 60. Ans - E.

Heseraj · Answer

First we can derive the rate of one workman as below: 
 20(R)*5=35 => R=\frac{7}{20}

Let X be the number of workmen needed and we have the work required (105) and the number of days worked (5) therefore,

\frac{X * 7}{20} * 5 = 105 => \frac{35X}{20} = 105 => 35 X = 105 * 20  = > divide both sides by 35 =>  x = 3*20 = 60

JeffTargetTestPrep · Answer

We are given that the rate of 20 workmen is 35/5 = 7 widgets per day. We need to determine how many workmen are needed for a rate of 105/5 = 21 widgets per day. We can let x = the number of workman and create the following proportion:

20/7 = x/21

(20)(21) = 7x

(20)(3) = x

60 = x

Answer: E

EMPOWERgmatRichC · Answer

Hi All,

When dealing with these types of 'work' questions, it can be helpful to think in terms of the total amount of work that needs to be done to complete the given task. We're told that it takes 20 workmen 5 days to complete the task. That's...

(20 men)(5 days each) = 100 work-days of effort to create 35 widgets.

Thus, there are a number of different ways to complete that work: 
1 worker can work for 100 days 
2 workers can work for 50 days each 
4 workers can work for 25 days each 
Etc.

The question asks us to create 105 widgets, which is 3 times the 35 in the above calculation. Those 105 widgets would take 3(100) = 300 work-days of effort. If we have to complete the job in 5 days, then we can set up the following equation:

(X men)(5 days each) = 300 work-days

X = 60 men

Final Answer:  E

GMAT assassins aren't born, they're made, 
Rich

D4kshGargas · Answer

Try this

20w----------5days------35 Widgets
 60w----------5days------105 Widgets 
(20 x 3 )_______________(35  x 3 )

TheNightKing · Answer

Since the number of days is the same and we can see the work to be completed is thrice of the given work unit, we can directly calculate the number of workmen as 20*3=60

OR

In a day 7 widgets are made by 20 workmen. We need 21 widgets in a day. So we will need 60 workmen to complete that task.

Answer E

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20 workmen can make 35 widgets in 5 days. How many workmen are needed

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