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# There are two tanks A, B. After 100 litres of water

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Manager
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There are two tanks A, B. After 100 litres of water  [#permalink]

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06 Mar 2018, 03:16
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Difficulty:

35% (medium)

Question Stats:

69% (01:43) correct 31% (01:51) wrong based on 119 sessions

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There are two tanks A, B. After 100 litres of water got drained from tank A and moved to to tank B, the volume of water in tank B increased by 20 percent. What was the original volume of water in tank A?

1) Before the 100 litres were drained and moved, the sum of the volume of water in the two tanks was 900 litres.
2) After the 100 litres were drained and moved, the volume of water left in tank A was half the volume of water in tank B.

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Re: There are two tanks A, B. After 100 litres of water  [#permalink]

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06 Mar 2018, 08:04
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1
Let, volume of water in tank A and B be V_a and V_b respectively. Given : 100 = (20/100)* V_b

Thus, V_b = 500 litres

Statement 1 : V_a + V_b = 900
Also, V_b = 500. Thus, V_a = 400.

Sufficient.

Statement 2 : After V_b = 500 + 100 = 600

V_a' = (1/2) V_b' = (1/2)* 600 = 300

V_a' = 300 + 100 = 400

Sufficient.

Thus, both statements are alone sufficient to answer the question.

I go with D.

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Re: There are two tanks A, B. After 100 litres of water  [#permalink]

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19 Mar 2018, 12:22

SOLUTION

We are given:
• After $$100$$ litres of water is moved from tank A to tank B, the volume of water in tank B is increased by $$20$$ percent.

Let us assume:
• The volume of water in tank A= x litres
• The Volume of water in tank B =y litres.

Thus,
• $$\frac{20}{100}$$$$*y$$=$$100$$
• $$y=500$$

We need to find:
• What is the value of $$x$$?

Statement-1: “Before the $$100$$ litres were drained and moved, the sum of the volume of water in the two tanks was $$900$$litres”.

• $$x + y= 900$$
• $$x = 400$$ litres

Thus, statement 1 alone is sufficient to answer the question.

Statement-2: “After the $$100$$litres were drained and moved, the volume of water left in tank A was half the volume of water in tank B”.
• $$x-100$$= $$\frac{1}{2}$$* (y+100)
• $$2x-200$$= $$500+100$$
• $$2x=800$$
• $$x=400$$

Thus, statement 2 alone is sufficient to answer the question.

We can find the answer by each of the statement alone.
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Re: There are two tanks A, B. After 100 litres of water  [#permalink]

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17 Sep 2018, 07:50
1
itisSheldon wrote:
There are two tanks A, B. After 100 litres of water got drained from tank A and moved to to tank B, the volume of water in tank B increased by 20 percent. What was the original volume of water in tank A?

1) Before the 100 litres were drained and moved, the sum of the volume of water in the two tanks was 900 litres.
2) After the 100 litres were drained and moved, the volume of water left in tank A was half the volume of water in tank B.

Dear Moderator,
Kindly retag this question to " Arithmetic " rather than " Work /rate problems". Thank you.
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- Stne

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Re: There are two tanks A, B. After 100 litres of water  [#permalink]

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17 Sep 2018, 07:54
stne wrote:
itisSheldon wrote:
There are two tanks A, B. After 100 litres of water got drained from tank A and moved to to tank B, the volume of water in tank B increased by 20 percent. What was the original volume of water in tank A?

1) Before the 100 litres were drained and moved, the sum of the volume of water in the two tanks was 900 litres.
2) After the 100 litres were drained and moved, the volume of water left in tank A was half the volume of water in tank B.

Dear Moderator,
Kindly retag this question to " Arithmetic " rather than " Work /rate problems". Thank you.

_______________
Fixed. Thank you.
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Re: There are two tanks A, B. After 100 litres of water  [#permalink]

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17 Sep 2018, 08:17
From the statement - Vol. of B is 500 litres (since 20% increase is 100 litres)
statement A - sum is 900 litres so 900-500 = 400 litres is the capacity of tank A.
statement B - after moving 100 litres, water left in tank A is 1/2 of tank B i.e. 500/2 = 250

both statements alone are sufficient. hence D
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Re: There are two tanks A, B. After 100 litres of water  [#permalink]

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17 Sep 2018, 10:30
itisSheldon wrote:
There are two tanks A, B. After 100 litres of water got drained from tank A and moved to to tank B, the volume of water in tank B increased by 20 percent. What was the original volume of water in tank A?

1) Before the 100 litres were drained and moved, the sum of the volume of water in the two tanks was 900 litres.
2) After the 100 litres were drained and moved, the volume of water left in tank A was half the volume of water in tank B.

100 litres of water drained from Tank A is 20% of initial volume of Tank B. Which means 20% of B's original water volume= 100 litres. Hence original volume of Tank B is known i.e. 500 litres(100*5)

1) Before the 100 litres were drained and moved, the sum of the volume of water in the two tanks was 900 litres.
Using this we can find the original volume of water in tank A as we already know the original volume of Tank B and from this statement we also know that total sum of both the tanks volume is 900. Hence this is Sufficient

2) After the 100 litres were drained and moved, the volume of water left in tank A was half the volume of water in tank B.
Using this statement also we can find the original volume in A, as A-100=1/2(B+100). Hence this statement is also Sufficient

Hence , the answer in D
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Re: There are two tanks A, B. After 100 litres of water &nbs [#permalink] 17 Sep 2018, 10:30
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