This is a Data Suff question from Official gmat prep.
The ratio of number of women to number of men to number of children in a room ia 5:2:7 respectively.What is the total number of people in the room.
1) The total number of women and children in the room is 12.
2)There are fewer than 4 men in the room.
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rakaisraka
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Brent@GMATPrepNow
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Target question: What is the total number of people in the room?The ratio of the number of women to the number of men to the number of children in a room is 5:2:7, respectively. What is the total number of people in the room?
(1) the total number of women and children in the room is 12.
(2) there are fewer than 4 men in the room.
Given: women : men : children = 5:2:7
So, there are many possible scenarios where the ratio is 5:2:7. Let's LIST a few:
Scenario #1: 5 women, 2 men, 7 children
Scenario #2: 10 women, 4 men, 14 children
Scenario #3: 15 women, 6 men, 21 children
Scenario #4: 20 women, 8 men, 28 children
.
.
.
and so on
Okay, now let's examine the statements:
Statement 1: the total number of women and children in the room is 12.
Let's check some of the scenarios that we LISTED.
Scenario #1: total number of women and children = 12 (NICE!)
Scenario #2: total number of women and children = 24 (no)
Scenario #3: total number of women and children = 36 (no)
...and so on.
We can see that ONLY scenario #1 fits the information in statement 1.
So, there MUST be 5 women, 2 men, and 7 children
In other words, the total number of people in the room MUST equal 14
Since we can answer the target question with certainty, statement 1 is SUFFICIENT
Statement 2: There are FEWER THAN 4 men in the room.
When we check some of the scenarios that we LISTED, we see that ONLY scenario #1 fits the information in statement 2.
So, there MUST be 5 women, 2 men, and 7 children
In other words, the total number of people in the room MUST equal 14
Since we can answer the target question with certainty, statement 2 is SUFFICIENT
Answer = D
Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
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Brent@GMATPrepNow
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I should point out that this question relies on our ability to recognize that in this REAL WORLD problem, we must use positive integers only .
So, while 0.5 : 0.2 : 0.7 is equivalent to the ratio 5:2:7, we cannot consider this scenario, since we cannot have 0.5 women, 0.2 men, and 0.7 children
Cheers,
Brent
So, while 0.5 : 0.2 : 0.7 is equivalent to the ratio 5:2:7, we cannot consider this scenario, since we cannot have 0.5 women, 0.2 men, and 0.7 children
Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
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rakaisraka
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Max@Math Revolution
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Forget conventional ways of solving math questions. In DS, Variable approach is the easiest and quickest way to find the answer without actually solving the problem. Remember equal number of variables and equations ensures a solution.
This is a Data Suff question from Official gmat prep.
The ratio of number of women to number of men to number of children in a room ia 5:2:7 respectively.What is the total number of people in the room.
1) The total number of women and children in the room is 12.
2)There are fewer than 4 men in the room.
==> women=w, men=m, children=c, from the original condition we have w=5k, m=2k, c=7k thus we have 4 variables (w,m,c,k) and 3 equations ( w=5k, m=2k, c=7k). Since we need to match the number of equations and variables, we need 1 more equation. We have 1 each in con 1) and con 2) thus D is likely the answer.
1) 5k+7k=12k=12 gives us k=1. The total number of people becomes 5K=2k+7k=14k=14, therefore it is sufficient.
2) 2k<4 , and since the number of people is an integer value, k=1. Thus we have, like 1), 14k=14 therefore it is sufficient.
The answer is D.
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This is a Data Suff question from Official gmat prep.
The ratio of number of women to number of men to number of children in a room ia 5:2:7 respectively.What is the total number of people in the room.
1) The total number of women and children in the room is 12.
2)There are fewer than 4 men in the room.
==> women=w, men=m, children=c, from the original condition we have w=5k, m=2k, c=7k thus we have 4 variables (w,m,c,k) and 3 equations ( w=5k, m=2k, c=7k). Since we need to match the number of equations and variables, we need 1 more equation. We have 1 each in con 1) and con 2) thus D is likely the answer.
1) 5k+7k=12k=12 gives us k=1. The total number of people becomes 5K=2k+7k=14k=14, therefore it is sufficient.
2) 2k<4 , and since the number of people is an integer value, k=1. Thus we have, like 1), 14k=14 therefore it is sufficient.
The answer is D.
If you know our own innovative logics to find the answer, you don't need to actually solve the problem.
www.mathrevolution.com
l The one-and-only World's First Variable Approach for DS and IVY Approach for PS that allow anyone to easily solve GMAT math questions.
l The easy-to-use solutions. Math skills are totally irrelevant. Forget conventional ways of solving math questions.
l The most effective time management for GMAT math to date allowing you to solve 37 questions with 10 minutes to spare
l Hitting a score of 45 is very easy and points and 49-51 is also doable.
l Unlimited Access to over 120 free video lessons at https://www.mathrevolution.com/gmat/lesson
l Our advertising video at https://www.youtube.com/watch?v=R_Fki3_2vO8
