DeeptiM wrote:

Fluke, pls I need help here..

Stmt1: In City H, 25 percent of the bilingual population is at least 30 years old.

Let the population of Bilingual be = 100

Then, 25% of Bilingual population (100) is at least 30yrs old.

i.e 25*100/100 = 25 people are bilingual and at least 30 yrs old.

Now,20% of x (population of people who are at least 30 years old) = 25

so x= 125...as we have the total population and no of ppl bilingual and atleast 30..we can find if it's at least 20%...isn't that sufficient?? what am i missing

Also, is there a simple way to explain statement2

I actually didn't get how you got the red part above.

Q: If there are x people who are at least 30, how many of them are bilingual?

1. In City H, 25 percent of the bilingual population is at least 30 years old.

It says just the reverse;

25% of bilinguals are at least 30.

Now, we know neither the total population nor the number of people who are at least 30. We just know that if there are 100 bilinguals among the people in H, 25 of those are at least 30 AND thus, 75 of those are less than 30.

CASE I:

Now, we take non-bilingual into account:

If there are 900 non-bilingual; out of those 900, all are less than 30 AND 0 person or none is at least 30.

Then

Total Population=Bilingual+Non-bilingual=100+900=1000

People who are at least 30= At least 30 among Bilinguals+At least 30 among non-Bilinguals=25+0=25

People who are at least 30= 25

People who are at least 30 AND bilinguals= 25

%=25/25=100%>20%

CASE II:

But, if

If there are 900 non-bilingual; out of those 900, none is less than 30 AND 900 people are at least 30.

Then

Total Population=Bilingual+Non-bilingual=100+900=1000

People who are at least 30= At least 30 among Bilinguals+At least 30 among non-Bilinguals=25+900=25

People who are at least 30= 925

People who are at least 30 AND bilinguals= 25

%=25/925= much less than 20%

We saw two cases:

First, in which % of bilinguals amongst people who are at least 30=100%

Second, in which % of bilinguals amongst people who are at least 30 less than 20%

So, just by knowing that "25 percent of the bilingual population is at least 30 years old" is NOT enough to find whether "at least 20% of the people in City H

who are at least 30 years old bilingual". Because, we don't know what's the population, how many are at least 30 etc...

Not Sufficient.

2. In City H, of the population at least 30 years old, 18 percent of the women and 17 percent of the men are bilingual.

Here, we are given ready-made what's been asked. Out of people who are at least 30; 18% bilingual women and 17% bilingual men.

No matter how many people are at least 30 year old; the % of bilinguals(men+women) will always be less than 20; because neither % of men is more than 20 nor that of women is.

e.g.

100 people out of 1million are at least 30.

Out of 100: 90 Men, 10 Women

(0.18*90+0.17*10) will always be less than 0.2(90+10)

x Men, y Women

0.18x+0.17y< 0.2x+0.2y=0.2(x+y)

Sufficient.

Ans: "B"

_________________

~fluke

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