Question

The cost of a notebook is Rs. 10ab. If Babu has Rs. (5a²b + 20ab² + 40ab). Then how many notebooks can he buy?

Answer 1

For Rs. 10ab the number of notebooks can buy = 1.

For Rs. (5a²b + 20ab² + 40ab) the number of notebooks can buy = ${\displaystyle \frac{\text{Total amount}}{\text{cost of 1 notebook}}}$

= ${\displaystyle \frac{5{\text{a}}^2\text{b}+20{\text{ab}}^2+40\text{ab}}{10\text{ab}}}$

= ${\displaystyle \frac{5{\text{a}}^2\text{b}}{10\text{ab}}+\frac{20{\text{ab}}^2}{10\text{ab}}+\frac{40\text{ab}}{10\text{ab}}}$

= ${\displaystyle \frac{1}{2}{\text{a}}^{2-1}{\text{b}}^{1-1}+2{\text{a}}^{1-1}{\text{b}}^{2-1}+4{\text{a}}^{1-1}{\text{b}}^{1-1}}$

= ${\displaystyle \frac{1}{2}{\text{a}}^1{\text{b}}^0+2{\text{a}}^0{\text{b}}^1+4{\text{a}}^0{\text{b}}^0}$

Number of notebook he can buy = ${\displaystyle \frac{1}{2}\text{a}+2\text{b}+4}$