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All questions of Direct and Inverse Variations for Class 8 Exam
In the context of direct variation, which statement is accurate?- a)The quantities are unrelated.
- b)The relationship is quadratic.
- c)The relationship is exponential.
- d)The relationship is linear, and the graph is a straight line.
Correct answer is option 'D'. Can you explain this answer?
In the context of direct variation, which statement is accurate?
a)
The quantities are unrelated.
b)
The relationship is quadratic.
c)
The relationship is exponential.
d)
The relationship is linear, and the graph is a straight line.
 | EduRev Class 8 answered |
In direct variation, the relationship between the two quantities is linear, represented graphically by a straight line passing through the origin.
If 108 kg of ration is sufficient for 18 students for 15 days, how many students can be supported by 70 kg for 25 days?- a)5 students
- b)15 students
- c)10 students
- d)7 students
Correct answer is option 'D'. Can you explain this answer?
If 108 kg of ration is sufficient for 18 students for 15 days, how many students can be supported by 70 kg for 25 days?
a)
5 students
b)
15 students
c)
10 students
d)
7 students
| | EduRev Class 8 answered |
The calculations show that 70 kg of ration can sustain approximately 7 students for 25 days based on the initial ratio of ration to students.
In a certain scenario, if the number of boys increases from 50 to 60, and the amount each boy receives decreases from ₹75, what will be the new amount each boy receives?- a)₹62.50
- b)₹80
- c)₹75
- d)₹60
Correct answer is option 'A'. Can you explain this answer?
In a certain scenario, if the number of boys increases from 50 to 60, and the amount each boy receives decreases from ₹75, what will be the new amount each boy receives?
a)
₹62.50
b)
₹80
c)
₹75
d)
₹60
 | C K Academy answered |
Using the inverse relationship, if the sum is constant, each boy will receive ₹62.50 when divided among 60 boys instead of 50.
If 30 men can build a wall in 50 days, how many men are needed to build a wall twice as large in 75 days?- a)40 men
- b)30 men
- c)50 men
- d)20 men
Correct answer is option 'A'. Can you explain this answer?
If 30 men can build a wall in 50 days, how many men are needed to build a wall twice as large in 75 days?
a)
40 men
b)
30 men
c)
50 men
d)
20 men
| | EduRev Class 8 answered |
To build a wall double in size in 75 days, calculations show that 40 men are needed (30 men for the original wall, adjusted for size and time).
If the ratio of two quantities is found to be constant at 3:1 for all pairs of values, what type of variation do they exhibit?- a)Direct variation
- b)Inverse variation
- c)Quadratic variation
- d)No variation
Correct answer is option 'A'. Can you explain this answer?
If the ratio of two quantities is found to be constant at 3:1 for all pairs of values, what type of variation do they exhibit?
a)
Direct variation
b)
Inverse variation
c)
Quadratic variation
d)
No variation
| | EduRev Class 8 answered |
A constant ratio of 3:1 indicates that the two quantities exhibit direct variation, meaning that as one increases, the other also increases proportionally.
If a car travels at a speed of 60 km/h, how long will it take to cover a distance of 120 km?- a)1 hour
- b)3 hours
- c)4 hours
- d)2 hours
Correct answer is option 'D'. Can you explain this answer?
If a car travels at a speed of 60 km/h, how long will it take to cover a distance of 120 km?
a)
1 hour
b)
3 hours
c)
4 hours
d)
2 hours
| | C K Academy answered |
Time is calculated using the formula: Time = Distance/Speed. Therefore, it will take 120 km / 60 km/h = 2 hours.
If the total work done by 3 men in a day is 1/30 of the work, how many days will it take for them to complete the work?- a)90 days
- b)120 days
- c)30 days
- d)60 days
Correct answer is option 'C'. Can you explain this answer?
If the total work done by 3 men in a day is 1/30 of the work, how many days will it take for them to complete the work?
a)
90 days
b)
120 days
c)
30 days
d)
60 days
 | Trisha Vashisht answered |
If 3 men complete 1/30 of the work in one day, they will finish the entire work in 30 days.
What is the relationship defined by direct variation?- a)When one quantity increases, the other also increases.
- b)When one quantity increases, the other decreases.
- c)When one quantity decreases, the other increases.
- d)When one quantity remains constant, the other varies.
Correct answer is option 'A'. Can you explain this answer?
What is the relationship defined by direct variation?
a)
When one quantity increases, the other also increases.
b)
When one quantity increases, the other decreases.
c)
When one quantity decreases, the other increases.
d)
When one quantity remains constant, the other varies.
| | Trisha Vashisht answered |
Direct variation occurs when one quantity increases and the other also increases, or when one decreases and the other decreases. This relationship is characterized by a constant ratio between the two variables.
What is the one-day work formula for completing a task?- a)Total work divided by total time
- b)Total work divided by total resources
- c)Total resources divided by total time
- d)Total time divided by total resources
Correct answer is option 'A'. Can you explain this answer?
What is the one-day work formula for completing a task?
a)
Total work divided by total time
b)
Total work divided by total resources
c)
Total resources divided by total time
d)
Total time divided by total resources
| | EduRev Class 8 answered |
The one-day work formula is calculated as the total work divided by the total time needed to complete that work. This helps determine how much work can be done in a single day.
A does a job in 80 days, and B does it in 100 days. If they work together for 20 days, how long will A take to finish the remaining work alone?- a)20 days
- b)44 days
- c)50 days
- d)40 days
Correct answer is option 'B'. Can you explain this answer?
A does a job in 80 days, and B does it in 100 days. If they work together for 20 days, how long will A take to finish the remaining work alone?
a)
20 days
b)
44 days
c)
50 days
d)
40 days
| | Trisha Vashisht answered |
After working together for 20 days, they complete part of the work. A's remaining work rate helps determine that A will take 44 more days to finish the task alone.
When using the arrow method for inverse proportion, how are the arrows generally represented?- a)Both arrows point upwards.
- b)Both arrows point downwards.
- c)Arrows are not used.
- d)One arrow points upward while the other points downward.
Correct answer is option 'D'. Can you explain this answer?
When using the arrow method for inverse proportion, how are the arrows generally represented?
a)
Both arrows point upwards.
b)
Both arrows point downwards.
c)
Arrows are not used.
d)
One arrow points upward while the other points downward.
| | Trisha Vashisht answered |
In the arrow method, for inverse proportion, one arrow points upward and the other downward to indicate the inverse relationship between the quantities.
How is the unitary method applied in direct variation?- a)By finding the average of all units.
- b)By dividing the total quantity by the number of units.
- c)By multiplying the value of one unit by the required number of units.
- d)By adding all values together.
Correct answer is option 'C'. Can you explain this answer?
How is the unitary method applied in direct variation?
a)
By finding the average of all units.
b)
By dividing the total quantity by the number of units.
c)
By multiplying the value of one unit by the required number of units.
d)
By adding all values together.
| | EduRev Class 8 answered |
The unitary method in direct variation involves finding the value of one unit and then multiplying this value by the number of units required to find the total.
If 4 workers can complete a task in 12 days, how many days will it take for 8 workers to complete the same task?- a)12 days
- b)6 days
- c)24 days
- d)30 days
Correct answer is option 'B'. Can you explain this answer?
If 4 workers can complete a task in 12 days, how many days will it take for 8 workers to complete the same task?
a)
12 days
b)
6 days
c)
24 days
d)
30 days
| | Trisha Vashisht answered |
Doubling the number of workers halves the time required to complete the task due to inverse variation, resulting in 6 days for 8 workers.
A fort has provisions for 300 men for 90 days. After 20 days, if 50 men leave, how long will the food last for the remaining men?- a)90 days
- b)84 days
- c)70 days
- d)100 days
Correct answer is option 'B'. Can you explain this answer?
A fort has provisions for 300 men for 90 days. After 20 days, if 50 men leave, how long will the food last for the remaining men?
a)
90 days
b)
84 days
c)
70 days
d)
100 days
| | Trisha Vashisht answered |
After 20 days, provisions for 300 men would last 70 days. For 250 men, the remaining provisions last 21,000 days divided by 250, resulting in 84 days of food.
How does the unitary method help in solving direct variation problems?- a)By finding the average of all quantities.
- b)By calculating the total value for one unit first.
- c)By ignoring the dimensions of the quantities.
- d)By establishing a constant ratio for all pairs.
Correct answer is option 'B'. Can you explain this answer?
How does the unitary method help in solving direct variation problems?
a)
By finding the average of all quantities.
b)
By calculating the total value for one unit first.
c)
By ignoring the dimensions of the quantities.
d)
By establishing a constant ratio for all pairs.
| | EduRev Class 8 answered |
The unitary method simplifies direct variation problems by first determining the value of one unit and then using it to find the total for multiple units.
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