Rationale: Distance covered by the car = 65 × 10 = 650 km
\ Speed = 650⁄5 = 130 km/hr
\ Speed gain = 130 – 65 = 65 km/hr
The answer: (C)
Question: A car finishes a journey in ten hours at the speed of 65 km/hr. If the same distance is to be covered in five hours how much more speed does the car have to gain?
Options:
(A) 8 km/hr
(B) 10 km/hr
(C) 65 km/hr
(D) 16 km/hr
(E) None of these
Reasoning: Given Exp. = (12)3 x 64 = (12)3 x 64 = (12)2 x 62 = (72)2 = 5184
432 12 x 62
Ans: (D)
Question: Find the value of y from (12)^3 x 6^4÷432 = y?
Options:
(A) 5618
(B) 5232
(C) 5889
(D) 5184
(E) 5132
Rationale: Speed downstream = d/t = 78/(4) = 20 kmph
Speed upstream = d/t = 56/(4) = 14 kmph
The speed of the stream = (20 - 14)/2 = 3 kmph
The answer: (E)
Question: A man rows his boat 78 km downstream and 56 km upstream, taking 4 hours each time. Find the speed of the stream?
Options:
(A) 6
(B) 5
(C) 7
(D) 8
(E) 3
Reasoning: Since the total number of skeins is X, then X = Blue + Yellow + Red
Because there are twice as many Blue as Yellow, then Blue = 2*Yellow
Thus X = 2*Yellow + Yellow + Red, which simplifies to X = 3*Yellow + Red
Because there are twice as many Yellow as Red, then Yellow = 2*Red
Thus X = 3*(2*Red) + Red, which simplifies to X = 7*Red
Therefore Red = X/7
Ans: (B)
Question: Suzy has a lot of skeins of yarn, she has blue, yellow, and red yarn. She has twice as much blue yarn as yellow yarn, and she has twice as much yellow yarn as she has red yarn. If she has X skeins of yarn, how many of the skeins are red, in terms of X?
Options:
(A) X/8
(B) X/7
(C) X/6
(D) X/5
(E) X/4
Rationale: N ends in the digit 1 because when N is divided by 10, the remainder is 1. Since N ends in 1, the remainder X when N is divided by 30 also ends in a 1. 11 is the only choice which ends in a 1.
The answer: (C)
Question: When N is divided by 10 the remainder is 1 and when N is divided by 3 the remainder is 2. What is the remainder X when N is divided by 30?
Options:
(A) (a)  4
(B) (b)  7
(C) (c)  11
(D) (d)  13
(E) (e)  17
Rationale: 1/6 â€“ 1/15 = 1/10
B can do the work in 10 days
The answer: (D)

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
Question: A and B together can do a work in 6 days. If A alone can do it in 15 days. In how many days can B alone do it?
Options:
(A) 7
(B) 13
(C) 19
(D) 10
(E) None