Twelve man take 6 hours to finish a piece of work. After the 12 men have worked for 1 hour, the contractor decides to call in 8 men so that the work can be completed earlier. How many more hours would 20 men take to complete the remaining work?

Answer 1

job requires 12(6) = 72 man-hours

They work for 1 hour, so 12 man-hours are used up, leaving 60 man-hours for the job to be done

Second shift has 20 men,
so time needed to complete the job
= 60 man-hours/20 men
= 3 hours

(the above applies only in theory, it does not apply to city workers or the like. Doubling the number of men on a job in practise does not cut the required time in half. , (this is supposed to be a joke) )

Answer 2

Thanks!

Answer 3

find the value of X
if 4x+2y=5 and 3x+y=2

Answer 4

solution:
x=?
4x+2y=5------------1 Equation
3x+y=2-------------2 Equation
2 equation multiply by 2
6x+2y=4------------3 Equation
1 equation sub by 3 equation
6x+2y=4
+(-)4x+(-)2y=(-)5
--------------------------
2x=-1
x=-1/2