Range of heights

[LevelOne]

Hi guys,

Can you help me with these questions, please?

All OAs will be posted. Thanks

Q1
For the students in class A, the range of their heights is r centimeters and the greatest height is g centimeters. For the students in class B, the range of their heights is s centimeters and the greatest height is h centimeters. Is the least height of the students in class A greater than the least height of the students in class B?

(1) r<s
(2) g>h

Q2
Did it take Pei more than 2 hours to walk a distance of 10 miles along a certain trail? (1 mile = 1.6 km, rounded to the nearest tenth).

(1) Pei walked this distance at an average rate of less than 6.4 km phr
(2) On average, it took Pei more than 9 min per km to walk this distance.

First one is clear to me, using ST = D; second can be any time, since it says 'more than'?? this is what slightly confuses me.

Q3
What is the value of 5x^2 + 4x - 1?

(1) x(x + 2) = 0
(2) x = 0

why is (1) not sufficient?

Q4
Is |x| > |y|?

(1) x^2 > y^2
(2) x > y

what theory would you use here?




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[anksgupta]

1. C as individualy we dont know about either greatest height or range.
combined we know that since greatest hieght of A is more and it has smaller range so least height of A ought to be greater than that of B

2. D in stem 2 it is saying on avg more than 9 mins are required to cover the distance so time to cover will be more than 9*16 = 144 mins. which is more than 2 hrs

3. B 1 gives 2 values of x: 0, -2 hence 2 diff value of expression . so 1 is not suff. 2. x=2 hence exp = -1 hence suffi. hence B

4. A from stem 1, taking roots on both side |x|>|y| hence suffi.
stem 2 is not enuf.

[LevelOne]

Thanks a lot, anksgupta. The OAs are the same as yours.