Question

in a library the ratio of mathematics book to science books is the same as the ratio of science books to hindi books.if there are 900 science books and 600 hindi books find the number of mathematics

Answer 1

x:y=y:z
x:900=900:600
x=1350

Answer 2

Let x, y and z represent science, maths and hindi books respectively.

ATQ, x:y=x:z
or,
$\frac{x}{y} = \frac{x}{z}$
or,
$\frac{900}{y} = \frac{900}{600}$
or,
$\frac{y}{900} = \frac{2}{3}$
or, y=600

Hence, there are 600 mathematics books.