The Ratio of Boys to Girls in Class A is 3 to 4. The Ratio of Boys to GMAT Problem Solving

Question: The ratio of boys to girls in Class A is 3 to 4. The ratio of boys to girls in Class B is 4 to 5. If the two classes were combined, the ratio of boys to girls in the combined class would be 17 to 22. If Class A has one more boy and two more girls than Class B, how many girls are in Class A?

1. 8
2. 9
3. 10
4. 11
5. 12

Answer: D
Solution and Explanation:
Approach Solution 1:
To solve this GMAT problem-solving question, you must use the information given in the question. The problems in this group come from many different areas of mathematics. This one has a lot to do with algebra.
The options are set up in a way that makes it hard to pick the best one. The candidates must know the right way to get the response they need. Only one of the five choices given is correct.
Given in the question that
There are 3 to 4 more boys than girls in Class A. For some positive integer multiple x, the number of boys is 3 and the number of girls is 4;
Boys outnumber girls in Class B by a ratio of 4 to 5: For some positive integer multiple y, the number of boys is 4 and the number of girls is 5;
In comparison to class B, class A has one extra boy and two more girls (3x = 4y+1 and 4x = 5y+2). Since we now have a system of two separate linear equations and two unknowns, we can solve it. When we solve for x, we obtain x=3. There are 4*3=12 girls since there are 4x as many girls in Class A.
Response: E.
As you can see, you did everything correctly; nonetheless, solving the system of equations would have been preferable to using a substitute.

Approach Solution 2:
To solve this GMAT problem-solving question, you must use the information given in the question. The problems in this group come from many different areas of mathematics. This one has a lot to do with algebra.
The options are set up in a way that makes it hard to pick the best one. The candidates must know the right way to get the response they need. Only one of the five choices given is correct.
As stated in the question,
If Class A boys are x and girls are y, then
Therefore, for class B, boys equal x-1 and girls equal y-1.
(x-1)/(y-2) = 4/5 and x/y = 3/4.
Adding the value of x to the second equation yields y = 12.
The only options are 8 and 12, as x must be an integer and y must be a multiple of 4 (since x must be an integer). For y = 8 and 12, we substitute 6 and 9 for x in the second equation to satisfy. Since (x-1)/(y-2) = (6-1)/(8-2)
is not equal to 4/5, the answer is 12.
E is the correct choice.

Approach Solution 3:
To solve this GMAT problem-solving question, you must use the information given in the question. The problems in this group come from many different areas of mathematics. This one has a lot to do with algebra.
The options are set up in a way that makes it hard to pick the best one. The candidates must know the right way to get the response they need. Only one of the five choices given is correct.
The ratios Ba (boys in A) to Ga (girls in A) and Bb (boys in B) to Gb can be established (girls in B).
Bb/Gb = 4/5 Ba/Ga = ¾
We want our ultimate ratio to be 17/22 when combined. Several multiples of each of the original ratios can be written out.
Ba/Ga = 3/4, 6/8, 9/12…
Bb/Gb = 4/5, 8/10, 12/15…
It is clear that choosing 9/12 for option A and 8/10 for option B will result in a combined ratio of 17/22. Thus, group A will consist of 12 girls.
E is the correct choice.

“The ratio of boys to girls in Class A is 3 to 4. The ratio of boys tol" - is a topic of the GMAT Quantitative reasoning section of GMAT. This question has been borrowed from the book “GMAT Official Guide Quantitative Review”.
To understand GMAT Problem Solving questions, applicants must possess fundamental qualitative skills. Quant tests a candidate's aptitude in reasoning and mathematics. The GMAT Quantitative test's problem-solving phase consists of a question and a list of possible responses. By using mathematics to answer the question, the candidate must select the appropriate response. The problem-solving section of the GMAT Quant topic is made up of very complicated math problems that must be solved by using the right math facts.

Suggested GMAT Problem Solving Questions:

• if 80 lamps can be lighted, 5 hours per day for 10 days for $21.25, then the number of lamps, GMAT Problem Solving
• Few of the corporate contributions to the earthquake relief fund, aside from Pterocom GMAT Problem Solving
• X is Older Than Y, Z Is Younger Than W And V Is Older Than Y GMAT Problem Solving
• What is the Largest Power of 3 Contained in 200! GMAT Problem Solving
• Find the Greatest Number That Will Divide 43,91 and 183 So as to Leave GMAT Problem Solving
• A Right Angled Triangle has its Sides in Arithmetic Progression and Being Integers GMAT Problem Solving
• Out of 7 Consonants and 4 Vowels, How Many Words of 3 Consonants and 2 Vowels Can be Formed? GMAT Problem Solving
• 4 Bells Toll Together at 9:00 A.M. They Toll After 7, 8, 11 and 12 seconds Respectively GMAT Problem Solving
• A Man can Hit a Target Once with 4 Shots. If He Fires 4 Shots in Success GMAT Problem Solving
• A is twice as good a workman as B and together they finish a piece of GMAT Problem Solving
• Frances can complete a job in 12 hours, and Joan can complete the same GMAT Problem Solving
• The Average Age of Chief Executive Officers (CEO’s) in a Large Sample of Companies is 57 GMAT Problem Solving
• Running at the Same Constant Rate, 6 Identical Machines can GMAT Problem Solving
• If a and b are positive integers such that a – b and a/b are both even GMAT Problem Solving
• If g is an integer what is the value of(−1)g4−1(−1)g4−1? GMAT Problem Solving
• What is the Area of the Triangle with the following Vertices L(1,3) M(5,1) and N(3,5)? GMAT Problem Solving
• If P2−QR=10P2−QR=10 ,Q2+PR=10Q2+PR=10 ,R2+PQ=10R2+PQ=10 GMAT Problem Solving
• If y (u-c) = 0 and j (u-k) = 0, Which of the Following Must be True, Assuming c < kc < k? GMAT Problem Solving
• What is the Remainder when 333^222 is Divided by 7? GMAT Problem Solving
• In a College of 300 Students, Every Student Reads 5 Newspapers and every Newspaper is Read by 60 Students GMAT Problem Solving
• If 4 People are Selected from a Group of 6 Married Couples, What is the Probability That none of Them would be Married to Each Other? GMAT Problem Solving
• If the Equation |x|+|y|= 5 Encloses a Certain Region on the Graph, What is the Area of that Region? GMAT Problem Solving
• If x = ¾ and y = ⅖ , What is the Value of √(x2+6x+9)(x2+6x+9) - √(y2−2y+1)(y2−2y+1)? GMAT Problem Solving
• A Chord of a Circle is Equal to its Radius. GMAT Problem Solving
• A Clock loses a Minute Every Three Hours for 4 Days and Gains 1% in the Subsequent 6 Days. GMAT Problem Solving
• The Population of the Bacteria Colony Doubles Every Day GMAT Problem Solving
• If tu=xytu=xyand ty=uxty=ux Where t, u, x, and y are Non-Zero Integers GMAT Problem Solving
• A Farm has Chickens, Cows and Sheep. The Number of Chickens and Cows Combined is 3 Times the Number of Sheep. GMAT Problem Solving
• In how Many Different Ways Can a Group of 8 People be Divided into 4 Teams of 2 People Each? GMAT Problem Solving
• If m is Three Times n, and if 2n + 3 is 20% of 25, What is the value of m? GMAT Problem Solving
• If Ben Were to Lose the Championship, Mike would be the Winner GMAT Problem Solving
• A Train Travelling at a Certain Constant Speed takes 30 seconds GMAT Problem Solving
• The product of the first 10 prime numbers is closest to which of the following? GMAT Problem Solving
• There is a 120 liter mixture of alcohol and water. The ratio of alcohol to water is 7 : 5 GMAT Problem Solving
• An equilateral triangle ABC is inscribed in square ADEF, forming three right triangles GMAT Problem Solving
• A Furniture Store Sells Only Two Models of Desks, Model A and Model B. The Selling Price of Model A is $120 GMAT Problem Solving
• A contractor combined x tons of a gravel mixture that contained 10 percent gravel G GMAT Problem Solving
• There are 100 Apples in a Bag of which 98% are Green and Rest are Red GMAT Problem Solving
• How many litres of a 90% solution of concentrated acid needs to be mixed with a 75% solution GMAT Problem Solving
• Jug Contains Water And Orange Juice In The Ratio 5:7 . Another Jug Contains Water And Orange J GMAT Problem Solving
• The number of ways in which 8 different flowers can be seated to form a garland so that 4 particular flowers are never separated GMAT Problem Solving
• A train travels from Albany to Syracuse, a distance of 120 miles, at an average rate of 50 miles per hour GMAT Problem Solving
• The hexagon ABCDEF is regular. That means all its sides are the same length and all its interior angles are the same size. GMAT Problem Solving
• y varies directly as x and when x = 6, y = 24. What is the value of y, when x = 5? GMAT Problem Solving
• If k is an Integer and 2 < k < 7, for How Many Different Values of k is There a Triangle With Sides of Lengths 2, 7, and k? GMAT Problem Solving
• How many factors does 36^2 have? GMAT Problem Solving
• A number when divided successively by 4 and 5 leaves remainder 1 and 4 respectively GMAT Problem Solving
• Walking at 6/7 th of his usual speed, a man is 25 min too late GMAT Problem Solving
• An Inlet Pipe can Fill in an Empty Cistern in 30 minutes Whereas a leak in the Bottom of the Cistern can Empty a Filled Tank in 40 minutes GMAT Problem Solving
• A milkman cheats his customers by adding water to the milk he sells GMAT Problem Solving