Three commodities, their consumption and their prices in the years $1985$ and $1990$ are listed below:

Commodity	Consumption $\left(\mathrm{in} \mathrm{kg}\right)$	Price in $1985$ $\left(\mathrm{in} ₹/\mathrm{kg}\right)$	Price in $1990$ $\left(\mathrm{in} ₹/\mathrm{kg}\right)$
Rice	$90$	$14.00$	$18.00$
Wheat	$150$	$9.00$	$9.48$
Tea	$9$	$75.00$	$100.00$

The cost of living index for the year $1990$ taking $1985$ as the base year is equal to _____.

If the area of rectangle is increased by $13\%$ and its breadth is increased by $5\%$, then what is the percentage increase in its length? (Approximately) 

A man donated $6\%$ of his income to a charity and deposited $20\%$ of the rest in a bank. If he is left with $₹14,100$, then his income is _____.

Madhav's salary is first increased by $x\%$ and then decreased by $x\%$. As a result, his salary is decreased by $\frac{x^2}{100}\%$. Comment.

The quantities consumed and the cost per $\mathrm{kg}$ of the commodities for the years $1986$ and $1995$ are given in the table below:

The cost of living index for the year $1995$ taking $1986$ as the base year is equal to _____.

The price of an article increases by $10\%, 15\%, \text{and} 20\%$ in $3$ consecutive weeks. What is the approximate overall percentage increase for the $3$ weeks?

If $X$ is $30\%$ of $Z$ and $Y$ is $60\%$ of $Z$,then $X$ is what percentage of $Y$?

What percent of $150$ is $45$?

If $20\%$ of $30\%$ of a certain number is $3000$, then find the number.