West Bengal Board Solutions for Chapter: Percentage, Exercise 2: Let's work out - 11

The length of each arm of a square was increased by $10\%$. Let's work out the increase of percentage of area by the Rule of Three

The price of sugar has increased by $20\%$. Let's work out the percentage of decrease in consumption of sugar if the monthly expenses of sugar remains same.

When water freezes into ice, it increases in volume by $10\%$. Let's work out in percentage how much it will decrease in volume if the ice melts into water.

Due to use of high-yielding see Utpalbabu has got $55\%$ production hike in paddy cultivation. But for this the cost of cultivation has increased by $40\%$. Previously a yield of $₹3000$ was produced by investing $₹1200$. Let's work out whether his income will be increased or decreased after using high-yielding seeds.

This year the students of Nandalal. H. S school have passed $85\%$ in Bengali, $75\%$ in Maths and $65\%$ in both subjects scoring A+. If the number of students are $120$ then let's work out how many students got A+ only in Maths.

This year the students of Nandalal. H. S school have passed $85\%$ in Bengali, $75\%$ in Maths and $65\%$ in both subjects scoring A+. If the number of students are $120$ then let's work out how many students did not get A+ in both subjects.

The length, breadth and height of a room are $15 \mathrm{m}, 10 \mathrm{m}$ and $5 \mathrm{m}$ respectively. If the length, breadth and height are increased by $10\%$ each then work out the increase of the area of the four walls of the room.

In annual sports $20\%$ of the students took part in $100 \mathrm{m}$ race, $15\%$ of the students in $200 \mathrm{m}$ sprint and $10\%$ of the students took part in the long jump event. $5\%$ of the students took part in these three events. Let's work out the number of the students who did not take part in any of the events if the total number of the students were $780$.