## 1. If x is directly proportional to y, and x is 4 when y is 6, what is x when y is 9?

### Answer:

### Explanation:

x/y = 4/6. When y = 9, x = (4/6) * 9 = 6.

## 2. If the cost of 5 kg of apples is $10, the cost of 12 kg of apples would be:

### Answer:

### Explanation:

Directly proportional. Cost/kg = $10/5. For 12 kg: 12 * ($10/5) = $24.

## 3. As the speed of a car increases, the time taken to cover a certain distance:

### Answer:

### Explanation:

Speed and time are inversely proportional for a fixed distance.

## 4. If 6 workers can complete a job in 8 days, 12 workers would complete the same job in:

### Answer:

### Explanation:

Number of workers and time are inversely proportional. Double the workers, half the time.

## 5. If a is inversely proportional to b, and a is 10 when b is 5, what is a when b is 10?

### Answer:

### Explanation:

ab = constant. 10*5 = a*10. Thus, a = 5.

## 6. If 15 machines produce 150 widgets in 5 hours, 5 machines would produce 150 widgets in:

### Answer:

### Explanation:

Number of machines and time are inversely proportional for a fixed production.

## 7. The ratio of x to y is 3:4. If x is 15, then y is:

### Answer:

### Explanation:

x/y = 3/4. When x = 15, y = (4/3)*15 = 20.

## 8. If the cost of 8 notebooks is $32, the cost of 10 notebooks is:

### Answer:

### Explanation:

Cost and number of notebooks are directly proportional.

## 9. A car traveling at 80 km/h reaches a destination in 5 hours. If it traveled at 100 km/h, it would take:

### Answer:

### Explanation:

Speed and time are inversely proportional. The journey would be faster.

## 10. If the product of x and y is constant, then x and y are:

### Answer:

### Explanation:

If the product is constant, increasing one will decrease the other.

## 11. If the area of a rectangle is kept constant and the length increases, the breadth:

### Answer:

### Explanation:

For a fixed area, length and breadth are inversely proportional.

## 12. A car consumes 5 liters of petrol to travel 100 km. For a journey of 250 km, it would consume:

### Answer:

### Explanation:

Consumption and distance are directly proportional.

## 13. 8 pipes fill a tank in 6 hours. 4 pipes would fill the same tank in:

### Answer:

### Explanation:

Number of pipes and time are inversely proportional.

## 14. If 7 bags of rice weigh 49 kg, 10 bags would weigh:

### Answer:

### Explanation:

Weight is directly proportional to the number of bags.

## 15. If y = k/x (where k is a constant), then y and x are:

### Answer:

### Explanation:

As the value of x increases, y decreases for a constant k.

## 16. A fan consumes 50 watts in 1 hour. For 4 hours of usage, it would consume:

### Answer:

### Explanation:

Power consumption and time are directly proportional.

## 17. If a decreases as b increases, then a and b are:

### Answer:

### Explanation:

Increase in one results in a decrease in the other.

## 18. If 9 pens cost $27, 15 pens would cost:

### Answer:

### Explanation:

Cost and number of pens are directly proportional.

## 19. A journey of 600 km is completed in 8 hours. The speed of the vehicle is:

### Answer:

### Explanation:

Speed = Distance/Time.

## 20. If 3x = 2y, then x and y are:

### Answer:

### Explanation:

The ratio is constant.