1.Is X>Y?
1. (X-Y)/X>0
2). (X^2-Y^2)/X^2>0
Stmt 1) (X-Y)/X > 0 => 1-Y/X > 0 => 1 > Y/X => We can’t say nothing unless we know the sign of X. INSUFF
Stmt 2) (X^2-Y^2)/X^2>0 => X^2 > Y^2. Still nothing can be said till we know the relation between X and Y. INSUFF
Combining (1) and (2) actually gives us no further info. INSUFF
(E)
2. A plane traveled k miles in the first 96 minutes of flight time. If it completed the remaining 300 miles of the trip in t minutes, what was its average speed, in mils per hour, for the entire trip?
Average speed = Total Distance / Total Time = (k+300)*60/(96+t) [60 is multiplied to convert hrs from minutes]
3. Is the positive integer x an even number?
1). If x is divided by 3, the remainder is 2
2). If x is divided by 5, the remainder is 5
Stmt 1) x=3k+2 -> 3k could be add or even. So x could be odd or even. INSUFF
Stmt 2) doesn’t make sense! Remainder cannot be 5!
(E)
4. What is the tens digit of positive integer x?
1). X divided by 100 has a remainder of 30
2). X divided by 100 has a remainder of 30
Stmt 1) x=100k+30 => No matter what the value of k, the tens digit will always be 3. SUFF
Stmt 2) x=100k+30 => J
(D)