Q: How many two-digit numbers satisfy this property.: The last digit (unit's digit) of the square of the two-digit number is 7 ?
Options:
(A) 3
(B) 1
(C) 4
(D) 0
(E) 2
A: OK... Stream of consciousness: A number ending with 7 can never be a perfect square.
The answer is (D).

Q: What is the units digit of the expression 14^715^4?
Options:
(A) 0
(B) 8
(C) 4
(D) 6
(E) 3
A: OK... Stream of consciousness: I think answer on this one should be B too. Since we know that 14^7>15^4, as Will said one should always check if the number is positive.
The answer is (B).

Q: The speed of a boat in still water is 60kmph and the speed of the current is 20kmph. Find the speed downstream and upstream?
Options:
(A) 40, 68 kmph
(B) 40, 30 kmph
(C) 90, 60 kmph
(D) 40, 60 kmph
(E) 20, 60 kmph
A: OK... Stream of consciousness: Speed downstream = 60 + 20 = 80 kmph
Speed upstream = 60 - 20 = 40 kmph
The answer is (D).

Q: By how much is 70% of 120 greater than 35% of 200.
Options:
(A) 15
(B) 14
(C) 13
(D) 16
(E) 17
A:
OK... Stream of consciousness: (70/100) * 120 (35/100) * 200
84 - 70 = 14
The answer is (B).