If the ratio of boys to girls in a class is B and the ratio of girls to boys is G, then B+G is ………
If the ratio of boys to girls in a class is B and the ratio of girls to boys is G, then B+G is ………
A) greater than 1 or equal to 1
B) greater than 1
C) less than 1
D) equal to 1
2 Answers
Correct option is (B) greater than 1
Let there are x number of girls and y number of boys in the class.
The ratio of boys to girls in the class is B.
\(\therefore\) \(\frac xy\) = B _________(1)
The ratio of girls to boys in the class is G.
\(\therefore\) \(\frac yx\) = G _________(2)
Now, B+G \(=\frac xy+\frac yx\)
\(=\frac{x^2+y^2}{xy}\)
\(\because(x-y)^2\geq0\)
\(\Rightarrow x^2+y^2-2xy\geq0\)
\(\Rightarrow x^2+y^2\geq2xy\)
\(\Rightarrow\frac{x^2+y^2}{xy}\geq2>1\)
\(\Rightarrow\frac{x^2+y^2}{xy}>1\)
Hence, B+G > 1