1. The height of a tree increases by 20% every year. If the current height of the tree is 28.8 meters, what was its height 2 years ago?

2. The height of a tree increases by 20% every year. If the current height of the tree is 28.8 meters, calculate what its height was 2 years ago.

3. A tree's height increases by 20% annually. If the tree's current height is 36 meters, what was its height 2 years ago?

(a) 25 meter (b) 30 meter (c) 40 meter (d) 32 meter

4. In your uncle's factory, the value of a machine depreciates at a rate of 10% per year. If the current value of the machine is ₹6000, what will its value be after 3 years?

5. The current population of a city is 56,000. If the annual population decline rate is 20%, what will be the population of the city after 2 years?

(a) ₹ 35,000 (b) ₹ 35,840 (c) ₹ 53,840 (d) none of the above

6. If the length of a cuboid is increased by 10%, the width by 20%, and the height is decreased by 30%, what is the percentage change in its volume?

(a) 6.5 increased (b) 7.6 increased (c) 6.5decreased (d) 7.6 decreased

7. To raise a plot of land measuring 25.5 meters in length and 20.2 meters in width by filling it with soil up to a height of 1.5 meters, a pit is dug in the adjacent plot with dimensions 15.3 meters in length and 10.1 meters in width. What will be the depth of the pit?

(a) 5 meters (b) 10 meters (c) 15 meters (d) 20 meters

8. A classroom needs to be built for 40 students in such a way that each student gets 5 square meters of floor area and 25 cubic meters of space. If the length of the room is 20 meters, what should be its height?

(a) 5 meters (b) 7 meters (c) 9 meters (d) 11 meters

9. A girl of height 90 cm is walking away from the base of a lamp post at a speed of 1.2 m per second. If the height of the lamp post is 3.6 m, then what will be the length of her shadow after 4 seconds?

10. The current population of a city is 27,200. If the annual population growth rate is 15%, what will be the population of the city after 2 years?

(a) ₹ 91,972 (b) ₹ 59,972 (c) ₹ 25,972 (d) ₹ 35,972

11. If the population of a village decreases at a rate of 10% per year, then if the current population is 500 people, what will be the population after 2 years?

12. The population of a village increases at a rate of \(\cfrac{x}{2}\)% per year. If the current population is \(xy\), then after \(z\) years, the population will be —

13. If the current population of a village is \( 2p \) and the population increases by \( 2r\% \) per year, what will be the population after \( 2n \) years?

14. The value of a machine in my uncle’s factory depreciates at the rate of 10% per year. If the current value of the machine is ₹60,000, let’s determine what its value will be after 3 years.

15. A person first observes a bird flying at an angle of elevation of 60° towards the north, and after 5 minutes, sees it at an angle of elevation of 30° towards the south. If the bird is flying along the same straight line at a height of \(120\sqrt{3}\) meters, determine its speed in kilometers per hour.

16. If the volume of a cone with a height of 12 cm is 154 cubic cm, then what will be the radius of its base?

(a) 3.5 cm (b) 4.5 cm (c) 5 cm (d) 5.5 cm

17. If the price of a washing machine is ₹12,000 and the annual appreciation rate is 10%, what will be its price after 3 years?

(a) ₹ 14,972 (b) ₹ 15,972 (c) ₹ 12,152 (d) ₹ 12,972

18. The price of a mobile phone decreases by 5% annually. If its current price is ₹16,400, what will be its price after 2 years?

(a) ₹ 15,801 (b) ₹ 14,801 (c) ₹ 13,401 (d) ₹ 12,801

19. The current population of a city is 25,000. If the annual population growth rate is 10%, what will be the population after 2 years?

(a) 30,250 (b) 25,300 (c) 65,300 (d) none of the above

20. A tree's height increases by 20% per year. Its current height is 21.6 meters. Determine its height 3 years ago.

21. The population of Maharashtra is \(2\times 10^8\). If the population increases at a rate of 12.5% every two years, what will be the population after 6 years?

22. In Pahlampur village, the current population is 10,000. If the population increases annually at a rate of 3%, calculate and write what the population will be after 2 years.

23. The diameter of a right circular cone is 21 meters and its height is 14 meters. Calculate how much it will cost to paint the lateral surface of the cone at a rate of 1.50 rupees per square meter.

24. A person observes an aircraft from a certain location at an angle of elevation of 60°. After 15 seconds, from the same location, he sees the aircraft again at an angle of elevation of 30°. If the aircraft is flying along the same straight line at a height of \(1500\sqrt{3}\) meters, then what is its speed?

25. A girl with a height of 90 cm is walking at a speed of 1.2 meters/second. If the lamp is 3.6 meters high, then after 4 seconds, what will be the length of the girl's shadow?

(a) 4.8m (b) 2.4m (c) 1.6m (d) 0.8m

26. Standing in the middle of the field, Habu sees a flying bird first at an elevation angle of 30° to the north, and after 2 minutes, at an elevation angle of 60° to the south. If the bird is flying along a straight path at a constant height of \(50\sqrt{3}\) meters, then what is its speed?

27. The volumes of two perpendicular circular rings are equal. The ratio of their heights is 4:9, then what will be the ratio of their radii?

(a) 3:2 (b) 2:3 (c) 4:9 (d) 8:9

28. If the length, breadth, and height of a right rectangular prism are in the ratio 3:2:1 and its total surface area is 88 square centimeters, then what is its volume?

(a) 120 cubic cm (b) 64 cubic cm (c) 48 cubic cm (d) 24 cubic cm

29. If the radius of a right circular cone is kept constant and its height is increased by 10%, by what percentage will the volume increase?

(a) 10% (b) 11% (c) 12% (d) 14%

30. If each edge of a cube is increased by 20%, by what percentage will the total surface area increase?

(a) 40% (b) 42% (c) 44% (d) 46%