Question

A can complete a work in x days and B in (x+4) days. A and B together worked for 2 days then A left. B completed it in another 7 days. Find x.

Please help me.​

Answer 1

Answer:

24 days

Step-by-step explanation:

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 =24 days