The Student Room Group

Math question

At Donhampton High School the ratio of boys to girls is 7:5
Each student studies one language, Spanish or German.
3/5 of the girls studied Spanish.
168 girls studied German.
75% of the boys study Spanish.

How many boys study Spanish?
From the question we can see all the information is given about the girls.
3/5 study Spanish and 168 girls study German. If 3/5 study Spanish that means it is 60% of the girls doing this language leaving 168 girls being 40% of the amount of girls in the school.
Using this info we can work out how many girls there are in the school. 168 accounts for 40% of girls like I said therefore if you 168/0.4 it gives you 420 girls in the school.
We can now look at the ratio to work out the number of boys.
and we can see the 5 represent the girls. That means 5/12 are girls (12 is from 7 + 5) so we get the 420 girls that we worked out and divide that by the decimal of 5/12 (which is 0.416666666666). So 420/0.41666666666 is 1008 students altogether in the school in which looking back at the ratio 7/12 are boys so 1008 x 7/12 gives 588 boys or you could do a simple subtraction of 1008 minus 420 which would give you the same answer.
We know that 75% of boys study Spanish so we get 588 x 0.75 which gives 441 boys.
You do 588 - 441 which gives 147 boys
Hope this helps
Original post by K-pop0204
At Donhampton High School the ratio of boys to girls is 7:5
Each student studies one language, Spanish or German.
3/5 of the girls studied Spanish.
168 girls studied German.
75% of the boys study Spanish.

How many boys study Spanish?
Reply 2
Thank You so much, it helped me.:biggrin:
Original post by Hajra Momoniat
From the question we can see all the information is given about the girls.
3/5 study Spanish and 168 girls study German. If 3/5 study Spanish that means it is 60% of the girls doing this language leaving 168 girls being 40% of the amount of girls in the school.
Using this info we can work out how many girls there are in the school. 168 accounts for 40% of girls like I said therefore if you 168/0.4 it gives you 420 girls in the school.
We can now look at the ratio to work out the number of boys.
and we can see the 5 represent the girls. That means 5/12 are girls (12 is from 7 + 5) so we get the 420 girls that we worked out and divide that by the decimal of 5/12 (which is 0.416666666666). So 420/0.41666666666 is 1008 students altogether in the school in which looking back at the ratio 7/12 are boys so 1008 x 7/12 gives 588 boys or you could do a simple subtraction of 1008 minus 420 which would give you the same answer.
We know that 75% of boys study Spanish so we get 588 x 0.75 which gives 441 boys.
You do 588 - 441 which gives 147 boys
Hope this helps
Original post by K-pop0204
Thank You so much, it helped me.:biggrin:


Great :smile: If you have any more questions you can directly contact me and I'll see what I can do
Reply 4
Thank You so much:biggrin:
Original post by Hajra Momoniat
Great :smile: If you have any more questions you can directly contact me and I'll see what I can do
Original post by Hajra Momoniat
From the question we can see all the information is given about the girls.
3/5 study Spanish and 168 girls study German. If 3/5 study Spanish that means it is 60% of the girls doing this language leaving 168 girls being 40% of the amount of girls in the school.
Using this info we can work out how many girls there are in the school. 168 accounts for 40% of girls like I said therefore if you 168/0.4 it gives you 420 girls in the school.
We can now look at the ratio to work out the number of boys.
and we can see the 5 represent the girls. That means 5/12 are girls (12 is from 7 + 5) so we get the 420 girls that we worked out and divide that by the decimal of 5/12 (which is 0.416666666666). So 420/0.41666666666 is 1008 students altogether in the school in which looking back at the ratio 7/12 are boys so 1008 x 7/12 gives 588 boys or you could do a simple subtraction of 1008 minus 420 which would give you the same answer.
We know that 75% of boys study Spanish so we get 588 x 0.75 which gives 441 boys.
You do 588 - 441 which gives 147 boys
Hope this helps

147 boys study German not Spanish...
Reply 6
can you bee more specific plz

Quick Reply