35 girls and boys went walking. The ratio is 5 girls to every 2 boys. How many boys are there?
Answer (3)
5 x − g i r l s 2 x − b oys 5 x + 2 x = 35 7 x = 35 ∣ d i v i d e b y 7 x = 5 T h ere a re 10 b oys .
Set up a proportion:
In a sample of 5:2, you have 7 kids in all.
So the the ratio of boys to kids in a sample of 7 is 2:7.
So set up a proportion:
7 2 = 35 X
7x =70
X = 10
Therefore, 10 of the boys went walking.
There are 10 boys in the group. This is found by using the ratio of 5 girls to 2 boys, which totals 35 students. By calculating the individual value of each part of the ratio, we determine that 2 parts corresponds to 10 boys.
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