A can do a work in 9 days, B can do a work in 7 days, C can do a work in 5 days. A works on the first day, B works on the second day and C on the third day respectively that is they work on alternate days. When will they finish the work ?

Question

নিচের অপশন গুলা দেখুন

• [6 + (11/215)] days
• [7 + (215/345)] days
• [6 + (261/315)] days
• [5 + (112/351)] days

Answer 1

সঠিক উত্তর হচ্ছে: [6 + (261/315)] days

ব্যাখ্যা:

After day 1, A finishes 1/9 of the work.

After day 2, B finishes 1/7 more of the total work. (1/9) + (1/7) is finished.

After day 3, C finishes 1/5 more of total work. Total finished is 143/315.

So, after day 6, total work finished is 286/315.

 

Now remaining work =  29 /315

 

On day 7, A will work again 

 

Work will be completed on day 7 when A is working. He must finish 29/315 of total remaining work.

 

Since he takes 9 days to finish the total task, he will need 261/315 of the day. 

 

Total days required is 6 + (261/315) days.