RRB Paramedical Staff Nurse Model Paper 4

Given, tank filled by A in 2h and tank filled by B in 6h
Then, part of the tank filled in 1 h by pipe A=‌

1

2

Part of the tank filled in 1 h by pipe B=‌

1

6

According to the question,
Pipe A was opened at 10 am and till 11 am pipe A alone worked. So, part of the tank filed between 10 am to 11 am by pipe A=‌

1

2

Thus remaining work =1−‌

1

2

=‌

1

2

Now, remaining work will be done by both pipes (A+B)
Tank filled by (A + B) working together
=‌

xy

x+y

(where x=2,y=6)
=‌

2×6

6+2

=‌

12

8

=‌

3

2

h
Hence, half tank filled by (A+B)
=‌

3

2×2

h=‌

3

4

h
=‌

3

4

×60=45min
Hence. the tank will be filled at 11: 45 am