Answer: B) 1/6 Explanation: Total work is given by L.C.M of 72, 48, 36 Total work = 144 units Efficieny of A = 144/72 = 2 units/day Efficieny of B = 144/48 = 3 units/day Efficieny of C = 144/36 = 4 units/day   According to the given data, 2 x p/2 + 3 x p/2 + 2 x (p+6)/3 + 3 x (p+6)/3 + 4 x (p+6)/3 = 144 x (100 - 125/3) x 1/100 3p + 4.5p + 2p + 3p + 4p = 84 x 3 - 54 p = 198/16.5 p = 12 days.   Now, efficency of D = (144 x 125/3 x 1/100)/10 = 6 unit/day (C+D) in p days = (4 + 6) x 12 = 120 unit Remained part of work = (144-120)/144 = 1/6.

Resistivity : Resistivity is a measure of the resistance to the flow of electrons.  Conductivity : Conductivity is just the inverse of resistivity, σ = 1/ρ, where σ is conductivity and ρ is resistivity.   Example: Think of a pipe and water, the bigger the pipe, the easier water can flow and thus the lower the resistance.

Answer: C) Only b follows Explanation: Clearly, reducing the number of aspirants for admission to colleges or sending the students of well-to-do families to foreign countries for higher studies, is no proper solution. So, both I and III do not follow. The right solution is to increase the number of colleges so as t accommodate the increasing number of admission-seekers. So, only II follows.

Answer: C) 5% Explanation: Let 'R%' be the rate of interest From the given data, 25202400 = 1 + R10041 + R1003⇒1 + R100 = 6360⇒R = 5   Hence, the rate of interest R = 5% per annum.

Answer: A) 54 Explanation: In given Series, all the numbers except 54 are multiples of 5.

Answer: A) 70 kms Explanation: Let the time taken by train be 't' hrs. Then, 40t = 35t + 1560 40t = 35t + 35/4 t = 7/4 hrs Therefore, Required length of the total journey d = s x t = 40 x 7/4 = 70 kms.

1. How to find Speed(s) if distance(d) & time(t) is given:    Speed (S) = Distance (D)Time (T)     Ex: Find speed if a person travels 4 kms in 2 hrs? Speed = D/T = 4/2 = 2 kmph.   2.  Similarly, we can find distance (d)  if speed (s) & time (t) is given by   Distance (D) = Speed (S) x Time (T)   Ex : Find distance if a person with a speed of 2 kmph in 2 hrs? Distance D = S X T = 2 x 2 = 4 kms.    3.  Similarly, we can find time (t) if speed (s) &  distance (d) is given by   Time (T) = Distance (D)Speed (S)   Ex : Find in what time a person travels 4 kms with a speed of 2 kmph? Time T = D/S = 4/2 = 2 hrs.   4. How to convert  km/hr into m/sec :   P km/hr = P x 518 m/sec   Ex : Convert 36 kmph into m/sec? 36 kmph = 36 x 5/18 = 10 m/sec    5. How to convert  m/sec into km/hr :   P m/sec = P x 185 kmph.   Ex : Convert 10 m/sec into km/hr? 10 m/sec = 10 x 18/5 = 36 kmph.   6.  If the ratio of the speeds of A and B is a:b, then the ratio of the times taken by them to cover the same distance is b : a.   7.  Suppose a man covers a certain distance at x km/ hr and an equal distance at y km/hr . Then, the average speed during the whole journey is 2xyx+y km/hr.

Answer: A) Chemical Explanation: In rusting the Iron ore make a chemical reaction with the oxygen in the presence of water and environmental or atmospheric moisture to produce an Iron oxide. Iron oxide is otherwise called as rust. The rusting of iron is a chemical change because it is two substances reacting together to make a new substance.