A can do a piece of work in 8 days, while B can do it in 18 days. In how many days will the work be completed if they both work on alternate days starting with B?

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SSC CGL 2023 Tier-I Official Paper (Held On: 21 Jul 2023 Shift 4)
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  1. 11
  2. 12
  3. 10
  4. 10

Answer (Detailed Solution Below)

Option 1 : 11
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PYST 1: SSC CGL - English (Held On : 11 April 2022 Shift 1)
25 Qs. 50 Marks 12 Mins

Detailed Solution

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Given: 

A can do a piece of work in 8 days, while B can do it in 18 days. 

Concept used:

Efficiency = (Total work / Total time taken)

Efficiency = work done in a single day 

Calculation:

Let the total work is the 72 units (LCM of 8 and 18)

The efficiency of A is 72 / 8 = 9 units

The efficiency of Bi is  72 / 18 = 4 units

In 2 days they do 9 + 4 = 13 units

They do 65 units of work in 5× 2 = 10 days

Then B does 4 units in 1 day 

Then A does 3 units in 1/3 day 

Total number of days will be 10 + 1 + 1/3 = 11">3434Unknown node type: span34Unknown node type: span

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