# Direct and Inverse Proportions – Class 8 / MCQ

CBSE CLASS 8 MATHEMATICS
Direct and Inverse Proportions: Chapter 13/MCQ
Multiple Choice Questions

Choose the correct answers from the options given below:
1. Two quantities x and y are said to be in ————- proportion if they increase (decrease) together in such a manner that the ratio of their corresponding values remains constant.
A. Direct Proportion
B. Inverse Proportion
C. Equal Proportion
2. Two quantities x and y are said to be in ————- if an increase in x causes a proportional decrease in y and vice-versa in such a manner that the product of their corresponding values remains constant.
A. Direct Proportion
B. Inverse Proportion
C. Equal Proportion
3. x and y are said to vary directly if —————
A. xy = k, k is a positive number.
B. x/y = k, k is a positive number.
C. x + y = k, k is a positive number.
4. x and y are said to vary inversely if ————–
A. xy = k, k is a constant.
B. x/y = k, k is a constant.
C. x + y = k, k is a constant.
5. More the money deposited in a bank more is the interest earned. This is a case of ———————
A. Direct proportion
B. Inverse proportion
C. Equal proportion
6. For a given job, more the number of workers, less will be the time taken to complete the work. This is a case of ———-
A. Direct Proportion
B. Inverse proportion
C. Equal proportion
7. Which of the following are in inverse proportion?
A. The population of a country and the area of land per person.
B. Area of cultivated land and the crop harvested.
C. The time taken for a journey and the distance traveled in a uniform speed.
8. If 15 workers can build a wall in 48 hours how many workers will be required to do the same work in 30 hours?
A. 20
B. 22
C. 24
9. A train is moving at a uniform speed of 75 km/hour. How far will it travel in 20 minutes?
A. 15 km
B. 20 km
C. 25 km
10. If the cost of 1 kg of sugar is Rs 36, then what would be the cost of 3 kg sugar?
A. 12
B. 39
C. 108

1. Direct proportion
2. Inverse proportion
3. x/y = k, k is a positive number.
4. xy = k, k is a constant.
5. Direct proportion
6. Inverse proportion
7. The population of a country and the area of land per person.
8. 24
(Let the number of workers employed to build the wall in 30 hours be y.
This is a case of Inverse proportion.
So 48 x 15 = 30 x y
Therefore, y = 48 x 15/30 = 24)
9. 25 km
(Let the distance (in km) in 20 minutes be x and time taken (in minutes) to cover 250 km be x. This is a case of direct proportion.
So x = 75 x 20/60 = 25 km)
10. 108 rupees.