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On a school trip the ratio of the number of teachers to the number of students is
1:15
The ratio of the number of male students to the number of female students is 7:5
Work out what percentage of all the people on the trip are female students.
Give your answer correct to the nearest whole number.
(3 marks)

Respuesta :

Answer: 39%

Step-by-step explanation:

Given

The ratio of the number of teachers to the number of students is 1:15.

and the ratio of the number of male and female students is 7:5

Suppose the number of teachers is x. So, students become 15x

For the ratio of male to female, assume male is 7y, so female is 5y

The sum of the male and female students comprises the whole student community

[tex]\therefore 15x=7y+5y\\15x=12y\\5x=4y[/tex]

The percentage of female students on the trip is

[tex]\Rightarrow \dfrac{5y}{x+15x}\times 100\\\\\Rightarrow \dfrac{5y}{16x}\times 100\\\\\Rightarrow \dfrac{5\times \frac{5}{4}x}{16x}\times 100\\\\\Rightarrow \dfrac{625}{16}=39\%[/tex]