Question

Hemant can do a work in (x+28) days while Manoj can do the same work in (x+7)
days. If they work together then can complete 60% of work in 3/5x days. Find
value of x.
(1)14
(2)28
(3) 66
(4) 40
​

Answer 1

Answer:

Given A do a piece of work in x days and B do work in x+16 days

Then A one day work = x1 days

AND B one day work =x+161days

Then Both one day work =x1+x+161=x(x+16)x+16+x=x2+16x2x+16 

So both do work in 2x+16x2+16x days 

But both do work in 15 days

∴2x+16x2+16x=15

⇒x2+16x=30x+240

⇒x2−14x−240=0

⇒x2−24x+10x−240=0

⇒x(x−24)+10(x−24)=0

⇒(x−24)(x+10)=0

Then x−24=0,x=24

And x+10=0,x=−10

But work done is not negative

Then work done =40days