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In a fleet of 70 cars that are either black or white. What is the rati

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In a fleet of 70 cars that are either black or white. What is the rati [#permalink]

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New post 28 Mar 2018, 23:47
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In a fleet of 70 cars that are either black or white. What is the ratio of the number of black cars to the number of white cars in the fleet?

(1) The number of black cars is 10 more than twice the number of white cars.
(2) The ratio of the number of black cars to the number of cars in the fleet is 3/7 more than the ratio of the number of white cars to the number of cars in the fleet.

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Re: In a fleet of 70 cars that are either black or white. What is the rati [#permalink]

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New post 29 Mar 2018, 00:37
Statement 1: since we have only 2 colour options and the car can't be of both colours simultaneously.
B+W =70 and B=2W+10.
We can solve for B and W. Sufficient.
Statement 2: B/70 = W/70 +3/7.
Also B +W =70.
Can be solved for B and W.
Sufficient.
Answer D
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Re: In a fleet of 70 cars that are either black or white. What is the rati [#permalink]

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New post 01 Apr 2018, 22:05
Bunuel wrote:
In a fleet of 70 cars that are either black or white. What is the ratio of the number of black cars to the number of white cars in the fleet?

(1) The number of black cars is 10 more than twice the number of white cars.
(2) The ratio of the number of black cars to the number of cars in the fleet is 3/7 more than the ratio of the number of white cars to the number of cars in the fleet.


Given : B + W =70
To Find :\(\frac{B}{W}\)

Statement 1 :

B = 2W +10

Using this with the given equation (2 Variables , 2 Equations ) Upon solving we get W=20 B = 50

Sufficient

Statement 2 :

\(\frac{B}{70} = \frac{3}{10} + \frac{W}{10}\)

Using this with the given equation (2 Variables , 2 Equations ) Upon solving we get W=20 B = 50

Sufficient

Therefore Option D
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In a fleet of 70 cars that are either black or white. What is the rati [#permalink]

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New post 02 Apr 2018, 06:42
Given, the number of cars=70 and that the cars are either black or white.

Let B be the number of black cars and W be the number of white cars.

Thus, \(B+W=70\) -------------eqn (1)

From statement (1) we know,
\(B=2W+10\)-------------------eqn(2)
Using the linear equation of 2 variables approach, we can find the number of black and white cars.

Therefore, statement (1) is sufficient.


From statement (2) we know that,
\(\frac{W}{70}\)=\(\frac{3}{7}\)+\(\frac{B}{70}\)-----------eqn(3)
Again, using eqn(1) and eqn(3), we can solve for B and W through the linear equation of 2 variables approach

Therefore, statement (2) is sufficient.

Since both statements are individually sufficient,the correct answer is D.
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Re: In a fleet of 70 cars that are either black or white. What is the rati [#permalink]

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New post 18 Apr 2018, 00:03
Bunuel wrote:
In a fleet of 70 cars that are either black or white. What is the ratio of the number of black cars to the number of white cars in the fleet?

(1) The number of black cars is 10 more than twice the number of white cars.
(2) The ratio of the number of black cars to the number of cars in the fleet is 3/7 more than the ratio of the number of white cars to the number of cars in the fleet.


Given equation : B + W = 70 ----- I

St 1: B = 2W + 10 ----- II

From I and II we can calculate value of B and W cars, and hence, we can find the required ratios. Sufficient

St 2: B/70 = 3/7 + W/70 ------III

From I and III we can calculate value of B and W cars, and hence, we can find the required ratios. Sufficient

It's (D)
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Re: In a fleet of 70 cars that are either black or white. What is the rati   [#permalink] 18 Apr 2018, 00:03
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