Tanvy bought a watch for Rs 1980 including VAT at 10%.
Question: Tanvy bought a watch for Rs 1980 including VAT at 10%. Find the original price of the watch. Solution: Let the original price of the watch be Rsx. VAT = 10% of Rsx $=\mathrm{Rs} \quad\left(x \times \frac{10}{100}\right)$ $=\mathrm{Rs} \frac{10 x}{100}$ $\therefore$ Price including VAT $=\mathrm{Rs}\left(x+\frac{x}{10}\right)$ $=\operatorname{Rs} \frac{11 x}{10}$ Now, $\frac{11 x}{10}=1980$ $\Rightarrow x=\left(1980 \times \frac{10}{11}\right)$ = 1800 Hence, the original price of the wa...
Read More →Solve this
Question: Let $\mathrm{f}: \mathbf{R} \rightarrow \mathbf{R} ; \mathbf{f}(\mathbf{x})=\frac{x}{c}$, where $\mathbf{c}$ is a constant. Find (i) (cf) (x) (ii) $\left(\mathrm{c}^{2} \mathrm{f}\right)(\mathrm{x})$ (iii) $\left(\frac{1}{c} f\right)(x)$ Solution: Given: $\mathrm{f}(\mathrm{x})=\frac{x}{c}$ (i) To find:(cf) (x) $(c f)(x)=c . f(x)$ $=c .\left(\frac{x}{c}\right)$ = x Therefore, $(c f)(x)=x$ (ii) To find: $\left(c^{2} f\right)(x)$ $\left(c^{2} f\right)(x)=c^{2} \cdot f(x)$ $=c .\left(\fra...
Read More →Reena bought the following articles from a general store:
Question: Reena bought the following articles from a general store: (i) 1 tie costing Rs 250 with ST @ 6% (ii) Medicines costing Rs 625 with ST @ 4% (iii) Cosmetics costing Rs 430 with ST @ 10% (iv) Clothes costing Rs 1175 with ST @ 8% Calculate the total amount to be paid by Reena. Solution: (i) Cost of the tie $=$ Rs. 250 Sales $\operatorname{tax}=6 \%$ of Rs 250 $=$ Rs. $\left(250 \times \frac{6}{100}\right)$ $=$ Rs. 15 Hence, bill amount $=$ Rs $(250+15)$ $=$ Rs. 265 (ii) Cost of the medicin...
Read More →Differentiate the following functions with respect to x :
Question: Differentiate the following functions with respect to $x$ : $(\sin x)^{\log x}$ Solution: Let $y=(\sin x)^{\log x}$ Taking log both the sides: $\Rightarrow \log y=\log (\sin x)^{\log x}$ $\Rightarrow \log y=\log x \log \sin x\left\{\log x^{a}=\operatorname{alog} x\right\}$ Differentiating with respect to $x$ : $\Rightarrow \frac{d(\log y)}{d x}=\frac{d(\log x \log \sin x)}{d x}$ $\Rightarrow \frac{d(\log y)}{d x}=\log x \times \frac{d(\log \sin x)}{d x}+\log \sin x \times \frac{d(\log ...
Read More →Which of the following can make
Question: Which of the following can make a parallel beam of light when light from a point source is incident on it ? (a)Concave mirror as well as convex lens (b)Convex mirror as well as concave lens (c)Two plane mirrors placed at 90 to each other. (d)Concave mirror as well as concave lens. Solution: (a). Explanation :When a point source is placed at the focus of a concave mirror or a convex lens, light after reflecting from the concave mirror and light after refracting from a convex lens goes a...
Read More →Give reasons for the appearance
Question: Give reasons for the appearance of new combination of characters in the F2progeny. Solution: Independent Assortment: The two forms of a gene separate and pair independent of the two forms of other genes during gametogenesis and fertilisation. It causes new combination of characters, e.g.;...
Read More →Give the basic features
Question: Give the basic features of the mechanism of inheritance. Solution: Basic Features of Inheritance Unit Characters: An organism is made of a large number of characters, each of which behaves as a unit. Genes: Characters are controlled by genes. One Gene-One Character: A single gene generally controls one character. Location of Genes: Genes are located on chromosomes. Alleles: A gene may have two or more forms called alleles. They represent different traits of a character. Paired Alleles:...
Read More →In the above question,
Question: In the above question, what are combination of characters in F2progeny ? What are their ratios ? Solution: Round Yellow 9, Round Green 3, Wrinkled Yellow 3, Wrinkled Green -1 i.e., 9 : 3 : 3 : 1....
Read More →In the above question,
Question: In the above question, what are combination of characters in F2progeny ? What are their ratios ? Solution: Round Yellow 9, Round Green 3, Wrinkled Yellow 3, Wrinkled Green -1 i.e., 9 : 3 : 3 : 1....
Read More →Study the following cross showing
Question: Study the following cross showing self pollination in F1. Fill in the blank and answer the question that follows : Solution: Rr Yy (Round Yellow )....
Read More →In the following crosses,
Question: In the following crosses, write the characteristics of the progency Solution: (a) All Round Yellow (b) Round Yellow, Round Green, Wrinkled Yellow and Wrinkled Green in the ratio of 9 : 3 : 3 : 1. (c) All Wrinkled Green (et) All Round Yellow (Rr Yy)....
Read More →Evolution has exhibited greater stability of molecular
Question: Evolution has exhibited greater stability of molecular structures when compared with morphological structures. Comment on the statement and justify your opinion. Solution: Life is a highly organised system of biochemicals and their reactions. It is expressed inside the cells. They are the same right from bacteria to human beings. However, the method of procurement of the raw materials for forming bio-chemicals is not the same in various organisms. It has helped in avoiding cut throat c...
Read More →Give reasons why acquired characters
Question: Give reasons why acquired characters are not inherited. Solution: Many of the variations have no immediate benefit to the species. They function as preadaptations which can be beneficial under certain environmental conditions like heat tolerance variation if the temperature of the area rises....
Read More →Differentiate between inherited
Question: Differentiate between inherited and acquired characters. Give one example of each type. Solution:...
Read More →All the human races like Africans,
Question: All the human races like Africans, Asians, Europeans, Americans and others might have evolved from a common ancestor. Provide a few evidences in support of this view. Solution: All the human races have evolved from a common ancestor because they possess Common body plan Common structure Similar physiology Similar metabolism Similar chromosome number Common genes or genetic blue print Free interbreeding....
Read More →Bacteria have a simpler body plan
Question: Bacteria have a simpler body plan when compared with human beings. Does it mean that human beings are more evolved than bacteria. Provide a suitable explanation. Solution: Both bacteria and human beings perform all the activities of life and live comfortably in their environments. They, therefore, seem to be equally evolved. However, human beings have a far more complex organisation and differentiation which are absent in bacteria. Since complex organisation and differentiation develop...
Read More →Does geographical isolation of individuals
Question: Does geographical isolation of individuals of a species lead to formation of a new species ? Provide a suitable explanation. Solution: Yes. Geographical isolation of a population will lead to genetic drift as there will be no gene flow between it and the parent species. Inbreeding in small population will result in fixation of certain alleles and elimination of others. There will be change in gene frequency. Mutations will produce new alleles and hence a new gene pool. Accumulation of ...
Read More →A woman has only daughters.
Question: A woman has only daughters. Analyse the situation genetically and provide a suitable, explanation. Solution: A woman produces only one type of ova (22 + X) while her husband produces two types of sperms, gynosperms (22 + X) and androsperms (22 + Y) in equal proportion. It is a chance that each time the woman conceived, only the gynosperm fertilised the egg so that only daughters were born....
Read More →Why did Mendel choos
Question: Why did Mendel choose Pea plant for his experiments ? Solution: Mendel chose Garden Pea or Edible Pea (Pisum sativum) as his experimental material because of Easy availability of detectable contrasting traits of several characters, Flower structure normally allows self fertilization but cross fertilization can also be carried out easily. Annual nature of the plant, Formation of a large number of seeds by each plant, Requirement of little care except at the time of cross breeding....
Read More →Give the pair of contrasting traits of the following
Question: Give the pair of contrasting traits of the following characters in Pea plant and mention which is dominant and recessive Yellow seed Round seed Solution: Seed Colour: Yellow (dominant), green (recessive). Seed Shape: Round (dominant), wrinkled (recessive)....
Read More →Does the occurrence of diversity
Question: Does the occurrence of diversity of animals on earth suggest their diverse ancestry also ? Discuss this point in the light of evolution. Solution: Diversity of animals does not mean that they have diverse ancestry. Animals can be grouped into distinct lineages (e.g., mammals, birds, reptiles, annelids). Many of the lineages further show some similarities in basic traits indicating a common ancestry, e.g., vertebrates. Therefore, animals having a common ancestor in the remote past have ...
Read More →What are homologous structures ?
Question: What are homologous structures ? Give an example. Is it necessary that homologous structures always have a common ancestor ? Solution: Homologous structures or organs are those structures which have similar origin, similar development, similar internal structure and similar basic plan but show different external form and function, e.g., forelimbs of amphibians, reptiles, mammals and birds. Homologous structures are always have a common ancestry because otherwise there cannot be any sim...
Read More →A very small population of a species faces
Question: A very small population of a species faces a greater threat of extinction than a larger population. Provide a suitable genetic explanation. Solution: A small population is always at a risk of degeneration and extinction due to Excessive inbreeding that brings about inbreeding depression or degeneration, Fewer recombinations and variations which are otherwise essential for maintaining vitality and vigour of the species. Lesser adaptability to changes in the environment, Increased threat...
Read More →In human beings the satistical possibility
Question: In human beings the satistical possibility of getting either a male or female child is 50 : 50. Give suitable explanation. Solution: Human females (44 + XX) are homogametic, that is, they produce only one type of ova (22 + X). Human males are heterogametic. They produce two types of sperms (22 + X and 22 + Y) in equal proportion, that is, 50 : 50 ratio. The chance of male or female child is also 50 : 50, as there is equal chance of androsperm (22 + Y) or gynosperm (22 + X) fertilizing ...
Read More →Why do all the gametes formed in human
Question: Why do all the gametes formed in human females have an X-chromosome ? Solution: Human females are homogametic. Their generic constitution is 44 + XX The two sex chromosomes are similar. Their ova which are produced after meiosis carry a gametic constitution of 22 + X No other combination is possible....
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