Question

find the number of days to complete a work when A and B works together supposing that A alone takes 78 days and B alone takes 178 days to complete the work​

Answer 1

Step-by-step explanation:

A+B=8 days

B=12 days

So, let's take LCM of 16 and 24. That's 24.

Note: 24 unit is the total work

So, A and B do (24/8) = 3 unit work/day …(1)

And, B does (24/12) = 2 unit work/day …(2)

Equation(1)-(2)

{A+B-B=3–2=1}

A =(3–2)= 1 unit/day

Condition: B work 4 days alone and remaining work done by A.

So Work done by B= 2*4=8 units

Now, Left total work = 24–8=16 units

Remaining work done by A= 16/1=16 days

Formula: Total days required = ( left Total work)/(unit per day)

Finally answer = 16 days.