If the length and breadth of a rectangular field are increased,the area increases by $50 \%$. If the length is increased by $20 \%$,by what percentage was the breadth increased?

In a History examination,the average for the entire class was $80$ marks. If $10 \%$ of the students scored $95$ marks and $20 \%$ scored $90$ marks,what was the average marks of the remaining students of the class?

$A$ salesman is allowed $5 \frac{1}{2} \%$ discount on the total sales made by him plus a bonus of $\frac{1}{2} \%$ on the sales made over $₹ 10000$. If his total earnings are $₹ 1990$,find the total sales.

Suresh gave $40 \%$ of his income to his wife. He gave $25 \%$ of the remaining amount to his son. Of the remaining amount,he spent $60 \%$ on education. Now,the amount with him is $₹ 2700$. What is the amount he gave to his wife?

If an electricity bill is paid before the due date,one gets a reduction of $4 \%$ on the amount of the bill. By paying the bill before the due date,a person got a reduction of $₹ 13$. The amount of his electricity bill was:

Which one of the following shows the best percentage?