Question

A B and C can do a work in 10 days 12 days and 15 days respectively they started working together but a left the for 5 days before the finishing work. B also left the work after 2 days when A left. in how many days did the work complete?​

Answer 1

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Answer 2

Explanation

In 1 day A can do=(1/10)th of the work

In 1 day B can do=(1/12)th of the work

In 1 day C can do=(1/15)th of the work

In 1 day (A+B+C) can do=[(1/10)+(1/12)+(1/15)]th of the work

=15/60=(1/4)

In 1 day(B+C) can

do=[(1/12)+(1/15)]th of the work

=(3/20)

Now let the work is finished in x days

Now, (A+B+C) works for (x-5) days

So, (A+B+C) Worked=(x-5)(1/4)=(x-5)/4

Now,(B+C)worked for 2days

(B+C) worked =2*(3/20)=(3/10)

Now,C worked for rest 3days

So C worked=3*(1/15)=(1/5)

Now,

Total work=1

[(x-5)/4]+(3/10)+(1/5)=1

5(x-5) +(3*2)+(4)

=>----------------------------=1

20

=>5x-15=20

=>5x=35

=>x=35/5=7

THE WORK WILL BE COMPLETED IN 7 DAYS....

I HOPE THIS WILL HELP YOU TO UNDERSTAND THE BASIC OF THIS PROBLEM........