Answer: D) 1/7 Explanation: Multiplicative inverse is nothing but a reciprocal of a number.  It is defined as one of a pair of numbers that when multiplied with another number equals the number 1. Multiplicative inverse or reciprocal of 7 is  7 x n = 1 => n = 1/7.   Hence, Multiplicative inverse or reciprocal of 7 is  1/7.

Answer: A) 169 & 81 Explanation: Observe that in each column, square of sum of digits in the first row = Respective second row elements.   In the same way, square of sum of digits in the second row = Respective third row elements.   => 6+42=102=100   => 4+92=132=169   => 8+12=92=81.

Answer: D) 7.5 hrs Explanation: Ratio of times taken by A and B = 160 : 100A can do the work in 12 daysLet B can do the work in "D" days=> 160:100 = 12 : D=> D = 12 x 100/160 = 7.5 hrs

Answer: C) 6 m Explanation: The edge of the new cube is = 33+43+53 = a3 => a = 6 m.

Answer: A) 40 days Explanation: Let 1 man's 1 day work = x and 1 woman's 1 day work = y.Then, 4x + 6y = 1/8 and 3x + 7y = 1/10Solving these two equations, we get:x = 11/400 and y = 1/40010 woman's 1 day work = (1/400 x 10) = 1/40. Hence, 10 women will complete the work in 40 days.

Answer: D) 2 Explanation: Total Water reqduired = 5000 × 150 lit = 750,000 litres = 750 cu.m.   Volume of tank = 20 × 15 × 5 = 1500 Cu.m.   Number of days required =1500/750 = 2 days.

Answer: C) Both A & B Explanation: Brightness of bulb depends on both voltage and current. The brightness depends on power. Since we know that  Power (P) = Voltage x Current = V I So whether you increase the current or the voltage the brightness will increase.   Example Illustration:  If you connect a long bulb and a round bulb in series, the long bulb glows but the round bulb does not. Both of them have the same current flowing through them (they are in series) but the long bulb has a greater voltage across it because it has more resistance (even though V= IR is not obeyed exactly, voltage drop does depend on the resistance). If you connect a round bulb and a long bulb in parallel, however, it is the round bulb that is brighter because now the voltage across both bulbs is the same but the current is larger through the round bulb (smaller resistance).   Hence, the brightness of a bulb depends on power i.e, both voltage and current.

Answer: D) 60 kms Explanation: Let the distance be d.  d8-2-d8+2 = 4   => 2d = 120    => d = 60 kms.