Question

. 40% of the students in a class are from India
and 50% are girls. If 25% of the Indian
students are girls, what percentage of
non-Indian students are boys ?
35​

Answer 1

1. We have 50 students and 40% are girls.
2. If we multiply 50 with 2 it gives us 100 (50x2=100)
3. 40% is equal to 40/100
4. So there are forty girls in the class with supposedly 100 students.
5. If we do the subtraction it’s 100–40=60
6. And then we divide it by 2 because we multiplied the number of the students earlier 60/2=30

Answer: There are 30 boys in the class

Answer 2

Given:

40% of the students in a class are from India  and 50% are girls. If 25% of the Indian  students are girls, what percentage of  non-Indian students are boys ?

Solution:

Assume that the total number of students is 100.

Calculate the total number of the Indian student,

$\[\begin{array}{l} = 100 \times \frac{{40}}{{100}}\\ = 40\end{array}\]$

Therefore 40 students are from India. and reaming 60 are non-Indians students

Since, 25% of the Indian  students are girls,

Therefore,

$\[\begin{array}{l} = 40 \times \frac{{25}}{{100}}\\ = 10\end{array}\]$

Therefore 10 students from India are girls.

It is given that 50% of the students are girls,

Number of girls not belongs to India,

$\[\begin{array}{l} = 50 - 10\\ = 40\end{array}\]$

Now, calculate the percentage of  non-Indian students are boys,

$\[{\rm{ = }}\frac{{{\rm{Total}}\,{\rm{non - Indiand}}\,{\rm{students}}\, - {\rm{Number}}\,{\rm{of}}\,{\rm{girls}}}}{{{\rm{Total}}\,{\rm{students}}\,}} \times 100\]$

$\[\begin{array}{l} = \frac{{60 - 40}}{{100}} \times 100\\ = 20\% \end{array}\]$

Hence the percentage of  non-Indian students are boys is 20%.