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The average age of three boys is 15 years. If their ages are in ratio 3:5:7, the age of the youngest boy is

121 years
218 years
315 years
49 years

Answer:- 1

Explanation:-

Solution:

\begin{aligned} Sum of ages of three boys = 45 years \\ Now, (3 x + 5 x + 7 x) = 45 \\ O r, 15 x = 45 \\ O r, x = 3 \\ So, age of youngest boy \\ = 3 x = 3 \times 3 = 9 years \end{aligned}

$\eqalign{ & {\text{Sum}}\,{\text{of}}\,{\text{ages}}\,{\text{of}}\,{\text{three}}\,{\text{boys}} = \,45\,{\text{years}} \cr & {\text{Now}},\,\left( {3x + 5x + 7x} \right) = 45 \cr & Or,\,15x = 45 \cr & Or,\,x = 3 \cr & {\text{So,}}\,{\text{age}}\,{\text{of}}\,{\text{youngest}}\,{\text{boy}} \cr & = 3x = 3 \times 3 = 9\,{\text{years}} \cr}$

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", "dateCreated": "7/24/2019 10:09:12 AM", "author": { "@type": "Person", "name": "Nitin Sir" } }, "suggestedAnswer": { "@type": "Answer", "text": "

Solution:

\begin{aligned} Sum of ages of three boys = 45 years \\ Now, (3 x + 5 x + 7 x) = 45 \\ O r, 15 x = 45 \\ O r, x = 3 \\ So, age of youngest boy \\ = 3 x = 3 \times 3 = 9 years \end{aligned}

$\eqalign{ & {\text{Sum}}\,{\text{of}}\,{\text{ages}}\,{\text{of}}\,{\text{three}}\,{\text{boys}} = \,45\,{\text{years}} \cr & {\text{Now}},\,\left( {3x + 5x + 7x} \right) = 45 \cr & Or,\,15x = 45 \cr & Or,\,x = 3 \cr & {\text{So,}}\,{\text{age}}\,{\text{of}}\,{\text{youngest}}\,{\text{boy}} \cr & = 3x = 3 \times 3 = 9\,{\text{years}} \cr}$ ", "dateCreated": "7/24/2019 10:09:12 AM" } }

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