2. Represent the following situations in the form of quadratic equations:
(i) The area of a rectangular plot is 528 m2 . The length of the plot (in metres) is one more than twice its breadth. We need to find the length and breadth of the plot.
Answer
The area of a rectangular plot is 528 m2 .Let the breadth of the plot be x m .
The length of the plot (in metres) is one more than twice its breadth. We need to find the length and breadth of the plot.
Thus, the length of the plot is \( (2 x+1) \mathrm{m} \).
Area of a rectangle \( = \) Length \( \times \) Breadth
\( \therefore 528=\mathrm{x}(2 \mathrm{x}+1) \)
\( \Rightarrow 2 \mathrm{x}^{2}+\mathrm{x}-528=0 \) (required quadratic form)
(ii) The product of two consecutive positive integers is 306. We need to find the integers.
Answer
The product of two consecutive positive integers is 306. We need to find the integers.Let the consecutive integers be x and \( \mathrm{x}+1 \).
It is given that their product is 306.
\( \therefore \mathrm{x}(\mathrm{x}+1)=306 \)
\( \Rightarrow \mathrm{x}^{2}+\mathrm{x}-306=0 \) (required quadratic form)
(iii) Rohan's mother is 26 years older than him. The product of their ages (in years) 3 years from now will be 360. We would like to find Rohan's present age.
Answer
Let Rohan's present age be x .Given, Rohan's Mother is 26 years older than him
Hence, his mother's age \( =x+26 \)
3 years hence,
Rohan's age \( =\mathrm{x}+3 \)
Mother's age \( =\mathrm{x}+26+3 \)
\( =\mathrm{x}+29 \)
It is given that the product of their ages after 3 years is 360.
\( \therefore(\mathrm{x}+3)(\mathrm{x}+29)=360 \)
\( x^{2}+3 x+29 x+87=360 \)
\( \Rightarrow \mathrm{x}^{2}+32 \mathrm{x}-273=0 \) (required quadratic form)
NCERT Solutions for Class 10 Maths Chapter 4 Exercise 4.1 || CBSE Class 10 maths chapter 4 Ex 4.1
Download the Math Ninja App Now(iv) A train travels a distance of 480 km at a uniform speed. If the speed had been \( 8 \mathrm{~km} / \mathrm{h} \) less, then it would have taken 3 hours more to cover the same distance. We need to find the speed of the train.
Answer
Let the speed of train be \( x \mathrm{~km} / \mathrm{h} \).As speed \( = \) distance \( / \) time
\( \Rightarrow \) Time taken for travel \( 480 \mathrm{~km}=\frac{480}{x} h r s \)
In the second condition,
speed of train \( =(\mathrm{x}-8) \mathrm{km} / \mathrm{h} \)
Given that the train will take 3 hours more to cover the same distance.
Therefore, Time taken for traveling \( 480 \mathrm{~km}=\left(\frac{480}{x}+3\right) \mathrm{hrs} \)
Speed \( \times \) Time \( = \) Distance
\( (x-8)\left(\frac{480}{x}+3\right)=480\)
\(\Rightarrow 480+3 x-\frac{3840}{x}-24=480\)
\(\Rightarrow 3 x-\frac{3840}{x}=24\)
\(\Rightarrow 3 \mathrm{x}^{2}-3840=24 \mathrm{x}\)
\(\Rightarrow 3 \mathrm{x}^{2}-24 \mathrm{x}-3840=0\)
\(\Rightarrow \mathrm{x}^{2}-8 \mathrm{x}-1280=0 \text { (required quadratic form) }\)
NCERT Solutions for Class 10 Maths Chapter 4 Exercise 4.1 || CBSE Class 10 maths chapter 4 Ex 4.1
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