Quadratic Equations

A farmer prepares rectangular vegetable garden of area 180 sq meters. With 39 meters of barbed wire, he can fence the three sides of the garden, leaving one of the longer sides unfenced. Find the dimensions of the garden.

Let the length and breadth of the rectangular garden be $x$ and $y$ meter, respectively. Given: $x y=180 s q m.....(i)and$ $\begin{array}{l} 2 y+x=39 \\ \Rightarrow x=39-2 y \end{array}$ Putting the...

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A truck covers a distance of 150 \mathrm{~km} at a certain average speed and then covers another 200 \mathrm{km} at an average speed which is 20 \mathrm{~km} per hour more than the first speed. If the truck covers the total distance in 5 hours, find the first speed of the truck.

Let the first speed of the truck be $x \mathrm{~km} / \mathrm{h}$. $\therefore$ Time taken to cover $150 \mathrm{~km}=\frac{150}{x} h \quad\left(\right.$ Time $\left.=\frac{\text { Dis tan ce...

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In a class test, the sum of the marks obtained by \mathrm{P} in mathematics and science is 28 . Had he got 3 more marks in mathematics and 4 marks less in science, the product of marks obtained in the two subjects would have been 180 . Find the marks obtained by him in the two subjects separately.

Let the marks obtained by $P$ in mathematics and science be $x$ and $(28-x)$, respectively. According to the given condition, $\begin{array}{l} (x+3)(28-x-4)=180 \\ \Rightarrow(x+3)(24-x)=180 \\...

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Some students planned a picnic. The total budget for food was Rs. 2000 . But, 5 students failed to attend the picnic and thus the cost for food for each member increased by Rs. 20 . How many students attended the picnic and how much did each student pay for the food?

Let $x$ be the number of students who planned a picnic. $\therefore$ Original cost of food for each member $=$ γ $\frac{2000}{x}$ Five students failed to attend the picnic. So, $(x-5)$ students...

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In a class test, the sum of Kamal’s marks in mathematics and English is 40 . Had he got 3 marks more in mathematics and 4 marks less in English, the product of the marks would have been 360 . Find his marks in two subjects separately.

Let the marks of Kamal in mathematics and English be $x$ and $y$, respectively. According to the question: $x+y=40$ Also, $\begin{array}{l} (x+3)(y-4)=360 \\ \Rightarrow(x+3)(40-x-4)=360 \quad[\text...

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An express train takes 1 hour less than a passenger train to travel 132 km between Mysore and Bangalore (without taking into consideration the time they stop at intermediate stations). If the average speeds of the express train is 11 km/h more than that of the passenger train, find the average speed of the two trains.

Solution: Let us say, the average speed of passenger train =  x km/h. Average speed of express train = (x + 11) km/h Given, time taken by the express train to cover 132 km is 1 hour less than the...

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A cottage industry produces a certain number of pottery articles in a day. It was observed on a particular day that the cost of production of each article (in rupees) was 3 more than twice the number of articles produced on that day. If the total cost of production on that day was Rs.90, find the number of articles produced and the cost of each article.

Solution: Let us say, the number of articles produced be x. Therefore, cost of production of each article = Rs (2x + 3) Given, total cost of production is Rs.90 $\therefore ~x\left( 2x~+\text{ }3...

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Represent the following situations mathematically: (i) John and Jivanti together have 45 marbles. Both of them lost 5 marbles each, and the product of the number of marbles they now have is 124. We would like to find out how many marbles they had to start with. (ii) A cottage industry produces a certain number of toys in a day. The cost of production of each toy (in rupees) was found to be 55 minus the number of toys produced in a day. On a particular day, the total cost of production was ` 750. We would like to find out the number of toys produced on that day.

(i) Let us say, the number of marbles John have = x. Therefore, number of marble Jivanti have = 45 – x After losing 5 marbles each, Number of marbles John have = x – 5 Number of marble Jivanti have...

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Represent the following situations in the form of quadratic equations: (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. (ii) A train travels a distance of 480 km at a uniform speed. If the speed had been 8 km/h less, then it would have taken

(iii) Let us consider, Age of Rohan’s = x  years Therefore, as per the given question, Rohan’s mother’s age = x + 26 After 3 years, Age of Rohan’s = x + 3 Age of Rohan’s mother will be = x + 26 + 3...

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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. (ii) The product of two consecutive positive integers is 306. We need to find the integers.

Solutions: (i) Let us consider, Breadth of the rectangular plot = x m Thus, the length of the plot = (2x + 1) m. As we know, $Area\text{ }of\text{ }rectangle\text{ }=\text{ }length~\times...

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