$A$ student has to secure $15\%$ marks to pass the examination. If he gets $80$ marks and fails by $70$ marks,find the maximum marks set for the examination.

$1200$ boys and $650$ girls appeared in an examination. If $70 \%$ of boys and $40 \%$ of girls failed,find the approximate percentage of passed students.

$A$ bag contains $600$ coins of $25$ paise and $1200$ coins of $50$ paise. If $12 \%$ of $25$ paise coins and $24 \%$ of $50$ paise coins are removed,the percentage of money removed from the bag is nearly: (in $\%$)

If $90 \%$ of $A = 30 \%$ of $B$ and $B = x \%$ of $A$,then the value of $x$ is

Rajeev buys goods worth Rs. $6650$. He gets a rebate of $6\%$ on it. After getting the rebate,he pays sales tax at the rate of $10\%$. Find the total amount he will have to pay for the goods.

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