RS Aggarwal - Mathematics

Book: RS Aggarwal - Mathematics

Chapter: 10. Quadratic Equations

Subject: Maths - Class 10th

Q. No. 24 of Exercise 10E

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24

A two – digit number is 4 times the sum of its digits and twice the product of its digits. Find the number.

Let the digits at units and tens places be x and y respectively.

Original number = 10y + x


According to the question


10y + x = 4(x + y)


10y + x = 4x + 4y


3x – 6y = 0


x = 2y – – – – (1)


also,


10y + x = 2xy


Using (1)


10y + 2y = 2.2y.y


12y = 4y2


y = 3


From (1) we get


x = 2.3 = 6


Original number = 10y + x


= (10.3) + 6 = 36


Chapter Exercises

Exercise 10A
Exercise 10B
Exercise 10C
Exercise 10D
Exercise 10E
Exercise 10F

More Exercise Questions

1

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2

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3

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4

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5

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7

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8

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11

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12

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13

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14

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18

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20

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21

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22

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23

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24

A two – digit number is 4 times the sum of its digits and twice the product of its digits. Find the number.
25

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26

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45

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46

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47

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52

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