Answer: B) 30 years Explanation: Let Karan’s present age be x years and Shiva’s present age be y years.Then, according to the first condition,x - 10 = 3(y - 10) or x - 3y = - 20 ..(1) Now, Karan’s age after 10 years = (x + 10) yearsShiva’s age after 10 years = (y + 10)(x + 10) = 2 (y + 10) or x - 2y = 10 ..(2) Solving (1) and (2), we get x = 70 and y = 30Karan’s age = 70 years and Shiva’s age = 30 years.

The commercialization of agriculture means that the agricultural crops and goods are produced by the peasants for sale in the market and not for their own consumption. Commercialisation of agriculture is a phenomenon where agriculture is governed by commercial consideration i.e. certain specialised crops began to be grown not for consumption in village but for sale in national and even in international market.   Commercialization of agriculture in India began during the British rule.

Answer: C) Ethylene Explanation: Allotropes are different structural modifications of an element, that is, each of two or more different physical forms in which an element can exist.   Carbon is capable of forming many allotropes due to its valency. Well-known forms of carbon include charcoal, diamond, graphite, buckminsterfullerene and graphene.   Hence, Ethylene is not an allotrope of Carbon.

Answer: D) 40 kgs Explanation: The fruit content in both the fresh fruit and dry fruit is the same. Let 'p' kgs of dry grapes are obtained from the 60 kgs of fresh grapes   => 60 x 40100 = p x 60100=> p = 40 kgs.   Therefore, 40 kgs of Dry grapes are obtained from 60 kgs of Fresh grapes.

Answer: B) Cl Explanation: The micronutrients (or trace minerals): boron (B), chlorine (Cl), manganese (Mn), iron (Fe), zinc (Zn), copper (Cu), molybdenum (Mo), nickel (Ni). and cobalt (Co).

Answer: D) Option 2,3 and 4 Explanation: when a cube is formed by folding the sheet shown in fig. (A), then   is one of the faces of the cube and this face lies opposite to a blank face. Also, a face bearing a square lies opposite to another blank face. The remaining two blank faces lie opposite to each other. Clearly, in the cube shown in fig. (1), the face consisting of the four symbols is not the same as that formed (as shown above). Hence, the cube in fig. (1) cannot be formed

Answer: B) 4 : 3 Explanation: Let us name the trains as A and B. Then, (A's speed) : (B's speed) = √b : √a = √16 : √9 = 4:3