Answer: C) 81 Explanation: Given the number series is 4, 6, 12, 30, 81, 315. Here it follows a pattern that 4 4 x 1.5 = 6 6 x 2 = 12 12 x 2.5 = 30 30 x 3 = 90 not equals to 81 90 x 3.5 = 315   Hence the odd one in the series is 81.

Answer: D) the capacity of layers of metal ions to slide over the other Explanation:

Answer: C) 10 Explanation: Let the price of each note book be Rs.x. Let the number of note books which can be brought for Rs.300 each at a price of Rs.x be y. Hence xy = 300 => y = 300/x (x + 5)(y - 10) = 300 => xy + 5y - 10x - 50 = xy =>5(300/x) - 10x - 50 = 0 => -150+x2+5x multiplying both sides by -1/10x => x2+15x-10x-150=0 => x(x + 15) - 10(x + 15) = 0 => x = 10 or -15 As x>0, x = 10.