Answer: D) 140 mts Explanation: Speeds of two trains = 30 kmph and 58 kmph => Relative speed = 58 - 30 = 28 kmph = 28 x 5/18 m/s = 70/9 m/s Given a man takes time to cross length of faster train = 18 sec   Now, required Length of faster train = speed x time = 70/9  x  18 = 140 mts.

Answer: C) 80% Explanation: circumference of A = 2πr = 8 => so r = 4πvolume = π×4π2×10 = 160πcircumference of B = 2πr   = 10 => so r = 5πvolume = π×5π2×8 =  200πso ratio of capacities = 160/200 = 0.8 so capacity of A will be 80% of the capacity of B.

Answer: A) 2Mg + O2 ----> 2MgO Explanation: Given Equation is  Mg + O2 → MgO Balancing the Chemical Equation is nothing but Conservation of Matter. As Matter is Neither created nor Destroyed, it must be conserved. Here we have 1 Mg and 2 O on the left side and 1 Mg and 1 O on the right side To balance that, add 1 Mg on the left side so that it becomes 2 Mg and 2 O on the left side i.e, 2 Mg + O2 → 2 MgO Here it has 2 Mg & 2 O on the left side and 2 Mg and 2 O on the right side and the Chemical equation is Balanced.

Answer: C) Sublimation Explanation: Sublimation is a process when a solid changes directly into gas instead changing into liquid first. Dry ice is an example of Sublimation process because it doesn't change into liquid CO2 and directly change into gaseous CO2 when heated.   Hence, Dry ice is an example of Sublimation process.

Answer: A) 29 Explanation: Let the five consecutive odd numbers be x-4, x-2, x, x+2, x+4 According to the question, Difference between square of the average of first two odd number and the of the average last two odd numbers is 396 i.e, x+3 and x-3 ⇒x + 32 - x - 32 = 396⇒ x2 + 9 + 6x - x2 + 6x - 9 = 396⇒ 12x = 396⇒ x = 33   Hence, the smallest odd number is 33 - 4 = 29.

Answer: C) 246 Explanation: A Committee of 5 persons is to be formed from 6 gentlemen and 4 ladies by taking.    (i) 1 lady out of 4 and 4 gentlemen out of 6  (ii) 2 ladies out of 4 and 3 gentlemen out of 6  (iii) 3 ladies out of 4 and 2 gentlemen out of 6  (iv) 4 ladies out of 4 and 1 gentlemen out of 6    In case I the number of ways = C14×C46 = 4 x 15 = 60  In case II the number of ways = C24×C36 = 6 x 20 = 120  In case III the number of ways = C34×C26 = 4 x 15 = 60 In case IV the number of ways = C44×C16 = 1 x 6 = 6    Hence, the required number of ways = 60 + 120 + 60 + 6 = 246

Answer: C) 12 Explanation: Given  1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 x 0 + 1 + 1 Using BODMAS Rule, As multiplication precedes addition, 1 x 0 = 0,  Now, 10 + 0 + 1 + 1 = 10 + 2 = 12.   Hence, 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 x 0 + 1 + 1 = 12.

Answer: D) 5 Explanation: By trial and error method, we get2880/3 = 960 is not a perfect square2880/4 = 720 is not a perfect square2880/5 = 576 which is perfect square of 24Hence, 5 is the least number by which 2880 must be divided in order to make it into a perfect square.