$860\%$ of $50 + 50\%$ of $860 = ?$

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

The percentage of metals in a mine of lead ore is $60 \%$. Now, the percentage of silver is $3/4 \%$ of the metals and the rest is lead. If the mass of ore extracted from this mine is $8000 \, kg$, what is the mass (in $kg$) of lead?

The sum of two numbers is $2490$. If $6.5\%$ of one number is equal to $8.5\%$ of the other,then the numbers are:

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.

$A$ number $x$ is $125 \%$ of $y$. To compute $y$,the number $x$ has to be multiplied by: