BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

help me with these questions

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Newbie | Next Rank: 10 Posts
Posts: 2
Joined: Tue Oct 06, 2009 11:21 pm

help me with these questions

by kimmie2k » Tue Oct 06, 2009 11:28 pm
1) if a>b>c>0, c=3?
1. 1/c > 1/3
2. 1/a + 1/b + 1/c = 1

Answer is D, Why?

2) John deposits $1000 in an account with annual rate x percent (compound quarterly), no other activity for this account, is account balance over $1050 after one year?
1. (1+x/200)^2 > 1.05
2. (1+x/400)^2 > 1.025

Answer is D, Why?


3) if |2x| > |3y|, is x>y?
1. x>0
2. y>0

Answer is A, why?

4) A(a,b) is the coodinate, is it on the line y=x?
1. a=2
2. b=a+2

Answer is B, Why?
Top
Source: — Data Sufficiency |
Junior | Next Rank: 30 Posts
Posts: 13
Joined: Sat Jul 25, 2009 9:30 am
Thanked: 2 times

by fiercepoint » Wed Oct 07, 2009 4:12 am
First problem.

1) Plug the value of c into the inequality, 1/3 > 1/3. This is not right so it is sufficient to say that c isn't 3.

2) Again plug the value into the inequality, 1/a + 1/b + 1/3 = 1. This means 1/a + 1/b would have to equal 2/3 but a>b>c>0 so 1/a and 1/b will both be smaller than 1/3. Adding two smaller fractions to 1/3 will not equal 1 so again this statement is sufficient to say that c isn't 3.
Top
Junior | Next Rank: 30 Posts
Posts: 13
Joined: Sat Jul 25, 2009 9:30 am
Thanked: 2 times

by fiercepoint » Wed Oct 07, 2009 4:29 am
I'll take the third one as well.

The absolute value of x is obviously higher than y but the problem is that x might be a larger negative number. For example if x = -2 and y = 1 then |2x| = 4 and |3y| = 3. All you need to know to solve this is whether x is positive or negative.

1) Tells you that x is positive. Sufficient.

2) Doesn't help at all, regardless of value of y, x could still be a larger negative number.
Top
Newbie | Next Rank: 10 Posts
Posts: 2
Joined: Tue Oct 06, 2009 11:21 pm

by kimmie2k » Wed Oct 07, 2009 10:24 pm
Thanks fiercepoint.

I understood your explaination on Q3.
and For Q1, I actually made a typo. Original question should be 1) if a>b>c>0, c<3?

Any idea?
Top
Post new topic Post Reply
• Page 1 of 1