$1$ quintal $25$ $kg$ is what percent of $1$ metric tonne?

The strength of a school increases and decreases in every alternate year by $10 \%$. It started with an increase in $2000$. Then the strength of the school in $2003$ as compared to that in $2000$ was

If the price of apples goes down by $10 \%,$ find the percentage of increase that a family should effect in its consumption so as not to increase expenditure on this account.

$A$ man's annual income has increased by ₹ $5$ lakhs,but the tax on income that he has to pay has reduced from $12 \%$ to $10 \%$. He now pays ₹ $10,000$ more income tax. What is his initial income (in ₹ lakhs)?

Two-thirds of three-fourths of one-fifth of a number is $15$. What is $30$ per cent of that number?

The price of sugar is reduced by $2 \%$. How many $kg$ of sugar can now be bought for the money which was sufficient to buy $49$ $kg$ of sugar earlier?