Question

A, B and C can do a piece of work in 20, 30 and
60 days respectively. In how many days can A do
the work will be completed if they each work in
alternative days?​

Answer 1

Answer:

fraction of work done is one by A,B and c is 1/20 ,1/30 and 1/60

in first 2 days , fraction of work completed by A is 2/20

third day ,B and c are assisting a then fraction of work completed on 3rd day will be 1/20 + 1/30 + 1/60 I.e 1/10

so total fraction of work done after 3 days 2/20 +1/10=4/20 I.e 1/5

Answer 2

ANSWER:-

Given:

A,B & C can do a piece of work in 20,30 & 60 days respectively.

To find:

How many days can A do the work will be completed if they each work in alternate days.

Solution:

⏺️A can do 1/20 of the work per day.

⏺️B can do 1/30 of the work per day.

⏺️C can do 1/60 of the work per day.

Therefore,

Together they can do 1/20 + 1/30+ 1/60 of the work per day.

But since B & C only help every third day, they can do on average,

1/20 + 1/3(1/30 + 1/60 ) of the work per day.

So,

$= > \frac{1}{20} + \frac{1}{3} ( \frac{1}{30} + \frac{1}{60} ) \\ \\ = > \frac{1}{20} + \frac{1}{3} ( \frac{2 + 1}{60} ) \\ \\ = > \frac{1}{20} + \frac{1}{3} ( \frac{3}{60} ) \\ \\ = > \frac{1}{20} + \frac{3}{180} \\ \\ = > \frac{9 + 3}{180} \\ \\ = > \frac{12}{180} \\ \\ = > \frac{1}{15}$

So,

they can do 1/15 of the work per day.

They can finish the job in 15 days.

Hope it helps ☺️