question: In 1 kg mixture of sand and iron, 20% is iron. How much sand should be added so that the proportion of iron becomes 10%?
Options:
(A) 1 kg
(B) 200 gms
(C) 800 gms
(D) 1.8 kg
(E) None of these
answer: Stream of consciousness: In 1 kg mixture quantity of iron = 200 gm
Let x gm sand should be added, then
10% of (1000 + x) = 200
\ x = 1000 gm = 1 kg The answer is (A).

q: A train running at the speed of 60 km/hr crosses a pole in 6 sec. What is the length of the train?
Options:
(A) 100 m
(B) 190 m
(C) 115 m
(D) 110 m
(E) 150 m
a: Stream of consciousness: Speed = 60 * 5/18 = 50/3 m/sec
Length of the train = speed * time = 50/3 * 6 = 100 m The answer is (A).

question: If the ratio of boys to girls in a class is B and the ratio of girls to boys is G; then 5 (B + G) is ?
Options:
(A) Equal to 3
(B) Less than 3
(C) More than 3
(D) Less than 1/3
(E) none of these
answer: Stream of consciousness: Let number of boys = x
Let number of girls = y
Therefore x/y = B and y/x = G
5(B + G) = 5[(x/y) + (y/x)] = 5[(x2 + y2)/xy] > 5 The answer is (E).

q: The speed of a boat in still water is 40kmph 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) 60, 20 kmph
a: Stream of consciousness: Speed downstream = 40 + 20 = 60 kmph
Speed upstream = 40 - 20 = 20 kmph The answer is (E).

question: 1,2,2,4,8,32,?(mult)
Options:
(A) 2816
(B) 1816
(C) 2812
(D) 2817
(E) 6816
answer: Stream of consciousness: Each number is the product of the previous two numbers, ie 8*32 = 2816. The answer is (A).

question: The sale price sarees listed for Rs.400 after successive discount is 10% and 5% is?
Options:
(A) 345
(B) 340
(C) 342
(D) 346
(E) 341
answer:
Stream of consciousness: 400*(90/100)*(95/100) = 342 The answer is (C).