Question

A can do a piece of work in 20 days and B in 15 days they worked together for 6 days and then A left how long will B take to finish the remaining work

Answer 1

HEY Buddy.....!! here is ur answer

Given that A can do a work in 20days and B can do the same work in 15 days.

Then L.C.M. of their work = 60

Then let the 60 is the total work which they have to do..

Then A do the work in a day = 60/20 = 3

and B do the work in a day = 60/15 = 4

when they work together they do work in a day = 4+3 = 7

A left after 6 days....then after 6 days the work that had finished = 7×6 = 42

Now remaining work = 60–42 = 18

So the B complete the remaining work in = 18/4 = 4 days 12 hour

I hope it will be helpful for you...!!

THANK YOU ✌️✌️

Answer 2

$\red{HEY\:BUDDY!!}$

HERE'S THE ANSWER...

____________________________

▶️ Making equations first..

♠️ A can do a piece of work in 20 days

⏺️ $\texttt{ A\:=\: 1/20}$ __( 1 )

♠️ B do that work in 15 days

⏺️ $\texttt{ B\:=\: 1/15}$ __( 2 )

♠️ Now A and B together do a work

⏺️ Adding eqn ( 1 ) and ( 2 )

=> $\texttt{ A + B \:=\: 1/20 + 1/15}$

⏺️ L.C.M. = 60

=> $\texttt{ A + B \:=\: ( 4 + 3 )/60}$

=> $\texttt{ A + B \:=\: 7/60}$

♠️ They worked together from 6 days

=> $\texttt{ A + B \:=\: ( 7 )( 6 ) /60}$

=> $\texttt{ A + B \:=\: 7/10}$

♠️ If A left and remain work had to be done by B

=> Remaining work = 1 - 7 / 10

=> $\boxed{ Remaining\:Work \:=\: 3/10}$

♠️The B will take to complete the remaining work

= 10/3 × 1/15

=> 10/45

♠️ So B will complete it in

=> 45/10

=> [ 4.5 days ]✔️✔️✔️

=> 2

HOPE HELPED...

$\red{JAI \:HIND..}$

PEACE ☺️✌️