7 men can do a piece of work in 12 days. How many men will be needed to do double the work in 8 days
Answers
Step-by-step explanation:
Given :-
7 men can do a piece of work in 12 days.
To find :-
How many men will be needed to do double the work in 8 days ?
Solution :-
Method-1:-
Given that
Number of men = 7
Number of working day they can finish the work
= 12 days
We know that
Number of men is inversely proportional to the number of working days
7 men can do the work in 12 days
Total working days = 7×12 = 84 working days
The double the working days = 2×84 = 168 days
Given number of days = 8
Let the number of men be X
=> Number of working days are required = 8X
=> 8X = 168
=> X = 168/8
=> X = 21
Men alredy working = 7
Required men for the work = 21-7 = 14
Method-2:-
Number of men (M1) = 7
Working days (D1) = 12
D2 = 8
Required Men (M2) = (7+X)
We know that
M1 D1 = 7×12 = 84
Double the work = 84×2 = 168
Now,
M2D2 =
(7+X)×8 = 168
=> 8X+56 = 168
=> 8X = 168-56
=> 8X = 112
=> X = 112/8
=> X = 1 4
Required men = 14
Answer:-
The required men are needed to the complete the double work in 8 days is 14
Used formulae:-
→ Number of men(M) is inversely proportional to the number of working days(D)
→ M ×D = Constant