Question

6 men can complete the electric fitting in a building in 7 days . How many days will it take 21 men to do the job.​

Answer 1

Answer:

6 men can complete the electric fitting in a building in 7 days, how many days will it take 21 men to do the job?

Lets solve the problem mathematically…assuming that all the men have equal potential of doing the task.

If 6 men can do the task in 7 days then…we can say that ……if no. of men increases then no. of days required decreases. i.e it follows a inverse relation(x is inversely proportional to y)

x= men req. y= hrs req.

Hence; x*y=k ……. Where k is const.

To find k …put x=6; y=7…..(given)

Hence we get; k=6*7=42

For x=21; 21*y=42

We get y=2

Hence, no. Of days days required for 21 men to complete the task is 2.

Step-by-step explanation:

This problem can be solved by Unitary method.

If 6 men can complete the electric fitting in a building in 7 days,

then 1 man will need 6 x 7 = 42 days to complete it.

Similarly 21 men can complete the job in 42/21 = 2 days.

hope will help!!

Answer 2

Answer:

2 days.

Step-by-Step Explanation:

→ 6 men can complete the electric fitting in a building in 7 days. So, $6 \ratio 7$

→ 21 men can do the job in $a$ days. So, $21 \ratio a$

We get,

$\therefore 6 \ratio 7 \ratio \ratio 21 \ratio a$

If the number of men will increase, So, the number of days for the job will decrease. Hence, here is inverse proportion.

If the number of men will increase, So, the number of days for the job will decrease. Hence, here is inverse proportion.Since in inversely proportional term, where x and y has two variations,

$\it x_1 x_2 = y_1 y_2 = k$

Where, k is a constant term.

Here,

x :- $x_1 = 6, \: x_2 = 7$

y :- $y_1 = 21, \: y_2 = a$

Therefore,

$\therefore \rm 6 \times 7 = 21 \times a$

$\implies \rm 42 = 21a$

$\implies \rm a = \frac{42}{21}$

$\implies \rm a = \cancel{\frac{42}{21}}$

$\implies \rm \bf a = 2$

Hence, 21 men can do that job in 2 days.