Answer: B) 13 days Explanation: Ratio of times taken by P & Q = 100 : 130 = 10:13   Let Q takes x days to do the work Then, 10:13 :: 23:x => x = 23x13/10 => x = 299/10   P's 1 day's work = 1/23 Q's 1 day's work = 10/299 (P+Q)'s 1 day's work = (1/23 + 10/299) = 23/299 = 1/13 Hence, P & Q together can complete the work in 13 days.

Answer: C) necessary centripetal force may be available from the horizontal component of the normal reaction due to the track to maintain the curved motion. Explanation: No circular or curved motion is possible without providing the necessary centripetal force. (C) provides this and so is the answer.

Answer: B) Rs. 150 and Rs.200 Explanation: Let the incomes of A and B be 3P and 4P. If each saves Rs. 100 per month, then their expenditures = Income - savings = (3P - 100) and (4P - 100).   The ratio of their expenditures is given as 1 : 2. Therefor, (3P - 100) : (4P - 100) = 1 : 2 Solving, We get P = 50. Substitute this value of P in 3P and 4P. Thus, their incomes are : Rs.150 and Rs.200

Answer: D) Carbon Explanation: Carbon is found in all organic compounds.

Let the two digits be x & y From given data in the question, we get x + y = 3(x - y) x + y = 3x - 3y => 2x = 4y x/y = 2/1 For having the 2:1, numbers satisfying are 12, 21, 24, 42, 36, 63, 48, 84 From this 36 is eleminated because it is a perfect square and no others are prime or perfect squares. Hence, there exists 7 such 2-digit numbers => 12, 21, 24, 42, 63, 48, 84.