CBSE Class 10-Mathematics: Chapter –4 Quadratic Equations Part 25

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Question 11:

A factory kept increasing its output by the same percent ago every year. Find the percentage if it is known that the output is doubled in the last two years.

Answer:

According to question,

Question 12:

Two pipes running together can fill a cistern in minutes. if one pipe takes minutes more than the other to fill it, find the time in which each pipe would fill the cistern.

Answer:

Let the faster pipe takes minutes to fill the cistern and the slower pipe will take minutes.

According to question,

Question 13:

If the roots of the equation are equal, prove that

Answer:

For equal root s,

Question 14:

Two circles touch internally. The sum of their areas is and the distance between their centers is . Find the radii of the circles.

Answer:

Let be the radius of two circles

According to question,

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Put the value of in eq. …(i)

When