The price of a house increases every year by $20 \%$. If the present price is $Rs \ 720000$,then what was its price (in $Rs$) $2$ years ago?

Krishnamurthy earns $₹ 15000$ per month and spends $80 \%$ of it. Due to pay revision,his monthly income has increased by $20 \%$ but due to price rise,he has to spend $20 \%$ more. His new savings are

Two-fifths of one-third of three-seventh of a number is $15$. What is $40$ per cent of that number?

$A$ number,when $35$ is subtracted from it,reduces to its $80$ percent. What is four-fifths of that number?

When $40$ is subtracted from $30 \%$ of a number,the result is $50$. What is the value of the number?

Two numbers are $50 \%$ and $80 \%$ less than a third number. By what percentage must the second number be increased to make it equal to the first number?