Pipes and Cistern can be solved by basic formula of TRW.

2. • Diksha Shivpure
• B.E (final year) CSE, WIT Solapur.
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3. *
W = R x T
T = W/R
R = W/T
Lcm(T) = Work(Imp)

4. Tank
Inlet Pipe
Outlet Pipe
R + ve
R – ve

5. Q1)Tina can do a piece of work in 12 days and Mina can
do it in 15 days. What time will they take to complete the
job if they work together?
60
T
5
M T+ M
T
R
12
4
15 60/9=20/3
9
W

6. Q2) A can complete a work in 10 days , B in 12 days and C in 15 days.
All of them began the work together, but A had to leave the work after
2 days of the start and B 3 days before the completion of the work,
How long did the work last?
60
A
6
B C
10
5
12 15
Total Time = 7days
A +
2
B +
15
C
4
12
T
R
C
3
4
30 18
2
9
CB +
W

7. Q3) A can do a piece of work in 120 days and B can do it in
150 days. They work together for 20 days. Then B leaves
and A continues the work alone. After 12 days C joins A
and the work gets completed in 48 days more . In how
many days can C do it if he works alone?
A
5
B
120
4
150
5
T
R
A
W 600
80
400
4
B
20
80
2.5
C
48
120
2.5
600

8. 1. If Jai and Bindu together can complete a job in 15 days and Jai alone can
complete it in 60 days. In how many days can
Bindu alone complete the job?
a)20 b)24 c)36 d)15 e)30
Answer=> A
J+B J B
15 60
4 1 3
60
20

9. 2. Rakesh can do a work in 18 days and Somesh can do the same work in 36
days. How many days will they take to complete the work by working
together?
a)24 b)20 c)18 d)10 e)12
Answer=> e
R S R+S
18 36 OR
2 1 3
36
12 18 * 36 = 12
54

10. 3. Two pipes X and Y can fill a cistern in 6 and 12 minutes respectively. How
long will it take to fill the cistern. If both pipes are opened simultaneously?
a)9 b)4 c)8 d)10 e)6
Answer => b)
X Y X+YS
6 12 OR
2 1 3
12
4 6 * 12 = 4
18

11. 4. Somu and Romu can do the job in 60 and 40 days respectively. They earned Rs.450 for
completing work. What is the share of Somu?
a)Rs.270 b) Rs.225 c)Rs.200 d)Rs.250 e)Rs.180
Answer => e)
R 1 / T
R1 = T2
R2 T1
R wa
R1 = wa1
R2 wa2
wa1 : wa2
2 : 3
T (5) A (450)
wa1 2 * 90 = 180
90

12. 5. A work 4 times as fast as B. If B completes a job in 60 days. Then in how many days
can A and B together complete the same job?
a)24 b)10 c)18 d)15 e)12
Answer = > d)
R(A) R(B)
4 1
T(A) T(B)
1 4
60
ab = 60 * 15 = 12
a + b 7515

13. 6. Raj and Sujay can complete the work in 10 and15 days respectively. Raj joins sujay after
some days and the whole work is completed in 9 days from the beginning. After how
many days did Raj join Sujay?
a)4 b)3 c)5 d)6 e)8
Answer = > C)
R S S R
T 10 15 9 4
R 3 2 2 3
30 18 12
S | | | Ans = 5
S+R ( 4 )

14. 7. Pradeep and Kartik can complete a job in 8 days and 24 days respectively. If
pradeep joins Kartik after 8 days, in how many day has the whole job been
completed?
a)11 b)20 c)9 d)14 e)12
Answer: e)
P K K P+K
T 8 24 8 4
R 3 1 1 4
24 8 16
Answer = 12