(Ans). (B)
(Question). There are 4 chess amateurs playing in Villa's chess club tournament. If each chess amateur plays with exactly 4 other amateurs, what is the total number of chess games possible to be played in the tournament?
Options:
(A) 10
(B) 8
(C) 40
(D) 60
(E) 120
(CoT). Each person is one participant of 4 games. So there are in all 4*4 = 16 instances of one participant games. But each game has 2 participants so total number of games = 16/2 = 8

(Ans). (B)
(Question). John has 13 ten-dollar bills, 11 five-dollar bills, and 17 one-dollar bills. If John needs to pay exactly $128, what is the least number of bills he will need to use?
Options:
(A) 14
(B) 16
(C) 17
(D) 19
(E) 20
(CoT). Any combination of ten-dollar and five-dollar bills cannot add up to amount ending with 8. John has to use at least 3 one-dollar bills. To gather the rest, $125, John needs to use a minimum of 13 bills: 12 ten-dollar bills and 1 five-dollar bill.

(Ans). (B)
(Question). A man rows his boat 75 km downstream and 45 km upstream, taking 2 1/2 hours each time. Find the speed of the stream?
Options:
(A) 1 kmph
(B) 6 kmph
(C) 5 kmph
(D) 8 kmph
(E) 7 kmph
(CoT). Speed downstream = d/t = 75/(2 1/2) = 30 kmph
Speed upstream = d/t = 45/(2 1/2) = 18 kmph
The speed of the stream = (30 - 18)/2 = 6 kmph

(Ans). (E)
(Question).
The average of 13 result is 20. Average of the first 8 of them is 20 and that of the last 8 is 40. Find the 8th result?
Options:
(A) 35
(B) 37
(C) 46
(D) 90
(E) 100
(CoT). Sum of all the 13 results = 13 * 20 = 260
Sum of the first 7 of them = 8 * 20 = 160
Sum of the last 7 of them = 8 * 40 = 320
So, the 8th number = 260 + 160 - 320 = 100.