Mathematics

There are 36 members in a student council in a school and the ratio of the number of boys to the number of girls is 3 : 1. How many more girls should be added to the council so ratio of number of boys to number of girls may be 9 : 5 ?

Ratio Proportion

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Answer

Ratio of the number of boys to the number of girls is 3 : 1.

Total members = 36

No. of boys = $\dfrac{3}{3 + 1} \times 36 = \dfrac{3}{4} \times 36 = 27.$

No. of girls = 36 - 27 = 9.

Let no. of girls to be added be x.

$\therefore \dfrac{27}{9 + x} = \dfrac{9}{5} \\[1em] \Rightarrow 135 = 9(9 + x) \\[1em] \Rightarrow 135 = 81 + 9x \\[1em] \Rightarrow 54 = 9x \\[1em] \Rightarrow x = 6.$

Hence, 6 girls must be added to council so ratio of number of boys to number of girls becomes 9 : 5.

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Mathematics

There are 36 members in a student council in a school and the ratio of the number of boys to the number of girls is 3 : 1. How many more girls should be added to the council so ratio of number of boys to number of girls may be 9 : 5 ?

Ratio Proportion

Answer

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Mathematics

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Ratio Proportion

Answer

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