The ratio of number of boys and girls in a school of 720 students is 7:5. How many more girls should be admitted to make the ratio 1:1?

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100

120

150

answer is B.

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Detailed Solution

Concept- We'll assume there are 5 more girls and 7 more boys in this situation. The value of x will then be determined by adding these numbers of boys and girls, taking it to equal 720, and then simplifying the resulting equation. The number of girls and boys will then be replaced with the x value mentioned above. The number of girls must match the number of boys in order for the ratio to be 1:1. To make the number of girls equal to the number of boys, we will thus add.
There are 7 more boys than girls, or a 7: 5 ratio.
Utilizing the property, we convert this part-to-part ratio to a part-to-whole ratio.

ratio of boys to all students

and the proportion of girls to all students is

We would first determine the precise number of boys and girls enrolled in the school before we could respond.
To do this, we multiply the total by the corresponding ratios.

Number of boys

and Number of girls

Now, we must establish a boys-to-girls ratio of 1:1.
For this, there should be an equal number of boys and girls.
By enrolling

girls in the school, this can be achieved.
Hence, the correct answer is option 2) 120

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