Ratios

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Ratios

by BTGmoderatorRO » Sun Dec 24, 2017 8:09 am
The number of singles that a baseball player hit increased 11 percent from her first season to her second season, and the number of doubles that she hit in the same time period decreased by 1 percent. If the total number of singles and doubles that she hit increased 2 percent from her first season to her second season, what is the ratio of the number of singles she hit in her first season to the number of doubles she hit in her first season?

(A) 1:3
(B) 9:11
(C) 1:1
(D) 2:1
(E) 11:3

OA is A

What is the best simple approach to this question? An Expert is needed here pls.Thanks
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by elias.latour.apex » Wed Dec 27, 2017 7:56 pm
This problem can easily be backsolved. Let's start by assuming that the woman in question hit 100 singles and 100 doubles. This is answer choice (C), a 1:1 ratio. With an 11% increase in singles and a 1% decrease in doubles, she will be hitting 111 singles and 99 doubles. Since our initial number of 100+100 = 200, a 2% increase will be 204. Are we there? Well, 111+99 = 210, so we can eliminate answer choices (C), (D), and (E).

Answer choice (B) feels too close to the 1:1 ratio, so let's try (A). Assume the woman hit 100 singles and 300 triples. With an 11% increase in singles and a 1% increase in doubles, she is now hitting 111 singles and 297 doubles. Since our starting numbers (100, 300) add to 400, a 2% increase will be 408. Does 111+297 total 408? Yes, they do. Accordingly (A) is the best answer.
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by GMATGuruNY » Wed Dec 27, 2017 10:27 pm
Roland2rule wrote:The number of singles that a baseball player hit increased 11 percent from her first season to her second season, and the number of doubles that she hit in the same time period decreased by 1 percent. If the total number of singles and doubles that she hit increased 2 percent from her first season to her second season, what is the ratio of the number of singles she hit in her first season to the number of doubles she hit in her first season?

(A) 1:3
(B) 9:11
(C) 1:1
(D) 2:1
(E) 11:3
This is a MIXTURE problem.
Percent change for singles = +11%.
Percent change for doubles = -1%.
Revenue change for the MIXTURE of singles and doubles = +2%.

The following approach is called ALLIGATION -- a very efficient way to handle MIXTURE PROBLEMS.
Let S = singles and D = doubles.

Step 1: Plot the 3 percent changes on a number line, with the percent changes for S and D on the ends and the percent change for the mixture in the middle.
S +11%....................+2%....................-1% D

Step 2: Calculate the distances between the percentages.
S +11%.......9.........+2%........3.........-1% D

Step 3: Determine the ratio in the mixture.
The ratio of S to D is equal to the RECIPROCAL of the distances in red.
S : D = 3:9 = 1:3.

The correct answer is A.

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by Scott@TargetTestPrep » Wed Sep 04, 2019 5:20 pm
BTGmoderatorRO wrote:The number of singles that a baseball player hit increased 11 percent from her first season to her second season, and the number of doubles that she hit in the same time period decreased by 1 percent. If the total number of singles and doubles that she hit increased 2 percent from her first season to her second season, what is the ratio of the number of singles she hit in her first season to the number of doubles she hit in her first season?

(A) 1:3
(B) 9:11
(C) 1:1
(D) 2:1
(E) 11:3

OA is A

What is the best simple approach to this question? An Expert is needed here pls.Thanks
Letting S = the number of singles in her first season and D = the number of doubles in her first season, we can create the equation:

1.11S + 0.99D = 1.02(S + D)

111S + 99D = 102S + 102D

9S = 3D

3S = D

S/D = 1/3

Answer: A

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