Question

The cost of Mathematics book is $Rs25\frac{3}{4}$ and that of Science book is $Rs20\frac{1}{2}$. Which costs more and by how much ?

Answer 1

Mathematics book costs $Rs.25\frac{3}{4}=Rs.\frac{103}{4}$

And Science book costs $Rs.20\frac{1}{2}=Rs.\frac{41}{2}$

To compare fractions we first make their denominators equal

For this we take the $L.C.M$ of$4$ and $2$ which is equal to $4$

So, we multiply the numerator and denominator by $2$ to get

$\Rightarrow \frac{41\times 2}{2\times 2}=\frac{82}{4}$

Clearly $\frac{103}{4}$ is greater is than $\frac{82}{4}$

Hence, Mathematics book costs more than Science book by $\frac{103}{4}-\frac{82}{4}=\frac{21}{4}=Rs.5.25$