Answer: C) 4 : 5 Explanation: Let their present ages be 13x and 17x.Then, 13x-4/17x-4 = 11/15. Solving this, we get x = 2.Required ratio = 13x2 + 6/17x2 + 6 = 32/40 = 4/5.

Answer: B) -2 Explanation: The sum of the oxidation numbers in a compound must equal zero. In the compound hydrogen sulfide, H2S, the two hydrogen atoms have an oxidation number of +1, for a total of +2. Therefore, the oxidation number of sulfur in the compound is -2, and the sum of the oxidation numbers is 0.

Answer: B) All living cells arise from pre-existing cells Explanation: All living cells arise from pre-existing cells is one component of the cell theory.   The Cell Theory is one of the basic principles of biology.   The Cell Theory states: 1. All living organisms are composed of cells. They may be unicellular or multicellular. 2. The cell is the basic unit of life. 3. Cells arise from pre-existing cells.

Answer: D) 29 yrs Explanation: Let the avg age of 7 boys be 'p' yearsLet the age of the girl be 'q' yearsFrom given data,The age of 7 boys = 7p yearsNow the new average = (p + 1) when 22 yrs is replaced by qNow the age of all 7 will become = 7(p + 1) yrsHence, 7p - 22 + q = 7(p + 1) yrs7p - 22 + q = 7p + 7q = 22 + 7 = 29 Therefore, the age of girl = q = 29 years.

Answer: C) 81 Explanation: The series follows the following pattern.   4   16 = 42   37 = 12+62   58 = 32+72   81 ≠52+82.   Here every number is based on the digits of previous number. Hence, 81 is the wrong number in the given series.

Answer: C) Nucleic acids Explanation: DNA stands for Deoxyribo nucleic acid. It is a nucleic acid made up of monomeric unit called Nucleotide. A nucleotide consist of - a) Sugar - Deoxyribose in DNA ( ribose in RNA) b) An organic base- Adenine, cytosine, guanine.

Answer: B) Urochrome Explanation: The yellow color of urine is due to the presence of a yellow pigment, urochrome. The color of normal urine is usually light yellow to amber. Generally the greater the solute volume the deeper the color.

Answer: A) 28 Explanation: Let the original number is 82 i.e 8 + 2 = 10 and when the digits are reversed i.e 28The difference is 82 - 28 = 54 i.e, the number is decreased by 54.