Questions: 10
Marks per Question: 3
Total Marks: 30
Allowed Duration: 60 Minutes
Write the full steps wherever needed. After submission, all keys will be shown together.

Q1. (3 marks)

The cost of 7 notebooks is ₹210. Find the cost of 12 notebooks if the cost is directly proportional to the number of notebooks.

Award Marks:
Key: Direct proportion. Cost of 1 notebook = 210 ÷ 7 = ₹30. Cost of 12 notebooks = 12 × 30 = ₹360.

Q2. (3 marks)

A car travels 180 km using 15 litres of petrol. How much petrol will it need to travel 300 km, assuming petrol consumption is directly proportional to distance?

Award Marks:
Key: 180 km → 15 L. 1 km → 15/180 L. 300 km → (15 × 300)/180 = 25 litres.

Q3. (3 marks)

12 workers can complete a job in 18 days. In how many days will 9 workers complete the same job, if the number of workers and days are inversely proportional?

Award Marks:
Key: Inverse proportion. Workers × Days = constant. 12 × 18 = 216 worker-days. Days for 9 workers = 216 ÷ 9 = 24 days.

Q4. (3 marks)

5 taps can fill a tank in 8 hours. How long will 10 similar taps take to fill the same tank?

Award Marks:
Key: Inverse proportion. 5 × 8 = 40 tap-hours. Time for 10 taps = 40 ÷ 10 = 4 hours.

Q5. (3 marks)

State whether the following is a case of direct or inverse proportion: “As the speed of a bus increases, the time taken to cover the same distance decreases.” Give a reason.

Award Marks:
Key: Inverse proportion, because when speed increases, time decreases for the same distance. One quantity increases while the other decreases in the same relation.

Q6. (3 marks)

15 metres of cloth cost ₹900. Find the cost of 22 metres of the same cloth.

Award Marks:
Key: Direct proportion. Cost per metre = 900 ÷ 15 = ₹60. Cost of 22 metres = 22 × 60 = ₹1320.

Q7. (3 marks)

8 men can build a wall in 21 days. How many men are required to build the same wall in 12 days?

Award Marks:
Key: Inverse proportion. Men × Days = constant. 8 × 21 = 168. Required men = 168 ÷ 12 = 14 men.

Q8. (3 marks)

Fill in the blank and identify the proportion: If 6 pencils cost ₹48, then 10 pencils cost ₹______. Also state whether it is direct or inverse proportion.

Award Marks:
Key: Cost of 1 pencil = 48 ÷ 6 = ₹8. Cost of 10 pencils = 10 × 8 = ₹80. This is direct proportion.

Q9. (3 marks)

A train moving at 60 km/h takes 5 hours to reach a destination. How much time will it take if the speed becomes 75 km/h?

Award Marks:
Key: Inverse proportion. Speed × Time = constant. 60 × 5 = 300. Time at 75 km/h = 300 ÷ 75 = 4 hours.

Q10. (3 marks)

Write one real-life example each for direct proportion and inverse proportion.

Award Marks:
Key: Example of direct proportion: More kilograms of rice, more total cost. Example of inverse proportion: More workers, less time needed to finish the same work.

Student Reflection

SaitechAI - Class 8 CBSE Maths Target Practice Worksheet