Exercise 10e

The distance between Mumbai and Pune is $192 \mathrm{~km}$. Travelling by the Deccan Queen, it takes 48 minutes less than another train. Calculate the speed of the Deccan Queen if the speeds of the two train differ by $20 \mathrm{~km} / \mathrm{hr}$

Let the speed of the Deccan Queen be $x \mathrm{~km} / \mathrm{hr}$. According to the question: Speed of another train $=(x-20) \mathrm{km} / \mathrm{hr}$ $\begin{array}{l} \therefore...

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A train travels at a certain average speed for a distanced of $54 \mathrm{~km}$ and then travels a distance of 63 $\mathrm{km}$ at an average speed of $6 \mathrm{~km} / \mathrm{hr}$ more than the first speed. If it takes 3 hours to complete the total journey, what is its first speed?

Let the first speed of the train be $x \mathrm{~km} / \mathrm{h}$. Time taken to cover $54 \mathrm{~km}=\frac{54}{x} h .$ New speed of the train $=(x+6) \mathrm{km} / \mathrm{h}$ $\therefore$ Time...

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A train covers a distance of $480 \mathrm{~km}$ at a uniform speed. If the speed had been $8 \mathrm{~km} / \mathrm{hr}$ less then it would have taken 3 hours more to cover the same distance. Find the usual speed of the train.

Let the usual speed of the train be $x \mathrm{~km} / \mathrm{h}$. $\therefore$ Reduced speed of the train $=(x-8) \mathrm{km} / \mathrm{h}$ Total distance to be covered $=480 \mathrm{~km}$ Time...

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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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The distance between Mumbai and Pune is $192 \mathrm{~km}$. Travelling by the Deccan Queen, it takes 48 minutes less than another train. Calculate the speed of the Deccan Queen if the speeds of the two train differ by $20 \mathrm{~km} / \mathrm{hr}$.

Let the speed of the Deccan Queen be $x \mathrm{~km} / \mathrm{hr}$. According to the question: Speed of another train $=(x-20) \mathrm{km} / \mathrm{hr}$ $\begin{array}{l} \therefore...

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A train travels at a certain average speed for a distanced of $54 \mathrm{~km}$ and then travels a distance of 63 $\mathrm{km}$ at an average speed of $6 \mathrm{~km} / \mathrm{hr}$ more than the first speed. If it takes 3 hours to complete the total journey, what is its first speed?

Let the first speed of the train be $x \mathrm{~km} / \mathrm{h}$. Time taken to cover $54 \mathrm{~km}=\frac{54}{x} h \quad\left(\right.$ Time $\left.=\frac{\text { Distance }}{\text { Speed...

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A train covers a distance of $480 \mathrm{~km}$ at a uniform speed. If the speed had been $8 \mathrm{~km} / \mathrm{hr}$ less then it would have taken 3 hours more to cover the same distance. Find the usual speed of the train.

Let the usual speed of the train be $x \mathrm{~km} / \mathrm{h}$. $\therefore$ Reduced speed of the train $=(x-8) \mathrm{km} / \mathrm{h}$ Total distance to be covered $=480 \mathrm{~km}$ Time...

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While boarding an aeroplane, a passengers got hurt. The pilot showing promptness and concern, made arrangements to hospitalize the injured and so the plane started late by 30 minutes. To reach the destination, $1500 \mathrm{~km}$ away, in time, the pilot increased the speed by $100 \mathrm{~km} /$ hour. Find the original speed of the plane. Do you appreciate the values shown by the pilot, namely promptness in providing help to the injured and his efforts to reach in time?

Let the original speed of the plane be $x \mathrm{~km} / \mathrm{h}$. $\therefore$ Actual speed of the plane $=(x+100) \mathrm{km} / \mathrm{h}$ Distance of the journey $=1500 \mathrm{~km}$ Time...

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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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A teacher on attempting to arrange the students for mass drill in the form of solid square found that 24 students were left. When he increased the size of the square by one student, he found that he was short of 25 students. Find the number of students.

Let there be $x$ rows. Then, the number of students in each row will also be $x$. $\therefore$ Total number of students $=\left(x^{2}+24\right)$ According to the question: $\begin{array}{l}...

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