$A$ fruit seller had some apples. He sells $40 \%$ of the apples and still has $420$ apples. Originally,how many apples did he have?

Fresh fruits contain $68 \%$ water and dry fruits contain $20 \%$ water. How much dry fruit can be obtained from $100 \,kg$ of fresh fruits?

$40 \%$ of $1640 + ? = 35 \%$ of $980 + 150 \%$ of $850$

For a rectangle,the length and breadth are increased by $10 \%$ and $20 \%$,respectively. The percentage increase in area is:

In $2009$,the food production was $5.5$ million tonnes and in $2010$,the production was $4.4$ million tonnes. Find out the percentage decrease in food production in these two years?

Twelve percent of Kaushal's monthly salary is equal to sixteen percent of Nandini's monthly salary. Suresh's monthly salary is half that of Nandini's monthly salary. If Suresh's annual salary is $Rs$ $1.08$ Lakhs,what is Kaushal's monthly salary?