Question

Each hole at the bottom of the tank empties it fully in 20 minutes.
What fraction of the tank will remain filled after 1 minute, when there are 2 holes?
[Picture shown is only for representation]
(A) -
20

After 20
minutes
After 1
minute

(B) - of tank
18
(C) -
(D)=
o of tank
20 of tank

Answer 1

Answer:

Given,

The first tap fills a tank in 20 minutes

The second tap fills a tank in 12 minutes

So,

In 1 minute first tank fills =

20

1

parts

In 1 minute 2

nd

tank fills =

12

1

parts

∴ In 1 minute both 1

st

and 2

nd

tap fills =

20

1

+

12

1

=

60

3+5

=

60

8

parts=

15

2

parts

∴ Both first and second tap will fill the tank in

(

15

2

)

1

minutes

=

2

15

minutes

=7

2

1

minutes

hence, the tank will be full in 7

2

1

minutes

Answer 2

Answer:

Ans.

(A)20

After 20 minute after 1 minute...