Question

9. The present ages of Arjun, Ravi and
Kiran are in the ratio of 3: 4: 5. Five
years ago the sum of their ages was 21.
Then the sum of the squares of their
present age is​

Answer 1

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┗─━─━─━─━∞◆∞━─━─━─━─┛

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Given :

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• Ratio of ages = 3 : 4 : 5

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To Find :

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• Sum of Squares of their present age

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Solution :

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Let their ages be 3x, 4x and 5x

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❄Hence, five years ago

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Age of Arjun

= 3x - 5

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Age of Ravi

= 4x - 5

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Age of Kiran

= 5x - 5

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According to question,

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$\bf \implies3x - 5 + 4x - 5 + 5x - 5 = 21$

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$\bf \implies12x - 15 = 21$

⠀⠀⠀⠀⠀⠀⠀⠀

$\bf \implies3(4x - 5) = 21$

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$\bf \implies4x - 5 = 21 \div 3$

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$\bf \implies4x - 5 = 7$

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$\bf \implies4x = 7 + 5$

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$\bf \implies4x = 12$

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$\bf \implies \: x = 12 \div 4$

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$\bf \implies \: x = 3$

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❄Present age of

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Arjun = 3x = 3 × 3 = 9yrs

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Ravi = 4x = 4 × 3 = 12yrs

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Kiran = 5x = 5 × 3 = 15yrs

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❄Sum of Squares of their present age

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$\bf = {9}^{2} + {12}^{2} + {15}^{2}$

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$\bf = 81 + 144 + 225$

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$\bf = 450$

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Therefore sum of Squares of their present age = 450

Answer 2

Answer:

450 is your answer...............