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Q1. 
A can do a piece of work in 12 days and B in 15 days. If they work on alternate days and A starts the work, In how many days will the work be complted? 
A. 14 

B. 13 ^{1} / _{4} 

C. 14 ^{1} / _{3} 

D. 12 ^{3} / _{4} 
Let the work = 60 units
A does 5 units on the first day
B does 4 units on the second day.
9 nuts are completed in 2 days
54 units in 12 days
Next day A does 5 units.
B completes 1 unit in 1/4 day.
Total = 12 + 1 + 1/4 = 13^{ 1}/_{4} days
Q2. 
A and B can complete a piece of work in 10 and 20 days respectively. If they work in alternate days, starting with A, in how many days will the work be completed? 
A. 10 

B. 11 

C. 12 

D. 13 
Let the total work to be completed = 20 units (LCM of 10 & 20)
On the first day, A can do 2 units of work
On the second day, B can do 1 unit of work
3 units of work will be completed in 2 days
18 units of work will be completed in 12 days.
Next day A will complete 2 units.
Hence total number of days = 12 + 1= 13 days
Q3. 
Ram and Shyam can complete a piece of work in 10 and 15 days respectively. If they work in alternate days, starting with Ram, in how many days will the work be completed? 
A. 6 

B. 10 

C. 12 

D. 16 
Let the total work to be completed = 30 units (LCM of 10 & 15)
On the first day, Ram can do 3 units of work
On the second day, Shyam can do 2 units of work
5 units of work will be completed in 2 days
30 units of work will be completed in 12 days.
Q1. 
A, B, and C can individually complete a piece of work in 48, 24, and 36 days respectively. If they work alternately, A on the first day, B on the second day, C on the third day, A on the fourth day and son. In how days will the work be completed? 
A. 33 ^{2} / _{5} 

B. 33 ^{1} / _{5} 

C. 33 ^{1} / _{3} 

D. 33 ^{1} / _{4} 
A, B, and C can individually complete a piece of work in 48, 24, and 36 days respectively.
Let the total work = 144 units
On the first day A does= 3 units
On the second day B does= 6 units
On the third day C does= 4 units
13 units are done in 3 days
143 units are done in 33 days
1 unit will be done by A in ^{1}/_{3} days.
Total number of days =33 ^{1}/_{3} days
Q1. 
Sanjeev, Sanjay, and Sumit can individually complete a piece of work in 36, 48, and 72 days respectively. Sanjay works on all the days. Sanjeev and Sumit join him every third day. In how many days will the work be completed? 
A. 33 ^{1} / _{3} 

B. 29 ^{1} / _{3} 

C. 31 ^{1} / _{3} 

D. 30 ^{2} / _{3} 
Sanjeev, Sanjay, and Sumit can individually complete a piece of work in 36, 48, and 72 days respectively. Sanjay works everyday. Sanjeev and Sumit join him every third day.
Let the total work = 144 units.
Sanjeev in one day does 4 units
Sanjay in one day does 3 units
Sumit in one day does 2 units
First 2 days, Sanjay does = 3 x 2 = 6 units
On third day they together do = 4 +3+2 = 9 units
15 units are completed in 3 days
135 units are completed in 9x3 =27days
9 units of work left
Sanjay does 6 units in the next 2 days
3 units will be done by all in 3/9 = 1/3 days
Total number of days = 27 + 2 + 1/3 = 29 ^{1}/_{3} days.