Answer: D) All the above Explanation: A pure substance can be defined as any single type of material that has not been contaminated by another substance. In chemistry, a pure substance has a definite composition. It can be a compound or an element. A pure substance is considered to be a material that consists of one type of "building block" of matter. Examples of pure substances include tin, sulfur, diamond, water, pure sugar (sucrose), table salt (sodium chloride) and baking soda (sodium bicarbonate). Tin, sulfur, and diamond are examples of pure substances which are chemical elements. All elements are pure substances. Water, sugar, salt and baking soda are pure substances which are chemical compounds. Chemical compounds also are pure substances

HURRAYS.

Answer: C) 10^7 ergs Explanation: 1 Joule = 107 ergs = 0.000239 Kilo Calories. Joule is the Unit of Energy. Joule is equal to Energy transferred to an object when a force of One Newton acts on that object in the direction of its motion through a distance of one metre.(1 N-m)

When the FTC was created in 1914, its purpose was to monitor all business practices to prevent unfair methods of competition in commerce as part of the battle to "bust the trusts."   Over the years, Congress passed additional laws giving the agency greater authority to police anticompetitive practices.

Answer: B) 4 yrs Explanation: Let the present age of Deepa = 5p Let the present age of Hyma = 6p After four years their ratio = 6 : 7 => 5p + 46p + 4 = 67 => 35p + 28 = 36p + 24 => p = 4 Therefore, the difference between their ages = 24 - 20 = 4 years.

We can make an equation: 3(100000 + x) = 10x+1 (Why? Well, adding 100000 puts a 1 at the front of a five-digit number, and multiplying by 10 and adding 1 puts a 1 at the end of a number) Solving this gives: 10x+1 = 3(100000 + x) 10x+1 = 300000 + 3x 10x = 299999 + 3x7x = 299999x = 299999/7 = 42857 The answer is 42857 (142857 is three times smaller than 428571).

Answer: D) 91 Explanation: Here in the given numbers 91 is a Composite number. Since it has factors of 7 and 13 other than 1 and itself.   Composite Numbers : A composite number is a positive integer which is not prime (i.e., which has factors other than 1 and itself). Examples :: 4, 6, 8, 12, 14, 15, 18, 20, ...

Answer: C) 2.83 kmph Explanation: Given speed of the person = 8 1/2 = 17/2 kmphLet the speed of the stream = x kmphspeed of upstream = 17/2 - xspeed of downstream = 17/2 + xBut given that,2(17/2 - x) = 17/2 + x=> 3x = 17/2=> x = 2.83 kmph.