Advertisements
Advertisements
Question
Three persons can build a small house in 8 days. To build the same house in 6 days, how many persons are required?
Advertisements
Solution
Let the number of persons required to build the same house in 6 days be x.
The number of persons and the number of days required to build the house are in inverse variation. So, the product of number of persons and the number of days required to build the house is constant.
∴ x × 6 = 3 × 8
⇒ x = ` (3 xx 8) /6 = 24/6 = 4`
∴ x = 4
Thus, 4 persons are required to build the same house in 6 days.
APPEARS IN
RELATED QUESTIONS
Rehman is making a wheel using spokes. He wants to fix equal spokes in such a way that the angles between any pair of consecutive spokes are equal. Help him by completing the following table:
| Number of spokes | 4 | 6 | 8 | 10 | 12 |
| Angle between a pair of consecutive spokes |
90° | 60° | ... | ... | ... |
- Are the number of spokes and the angles formed between the pairs of consecutive spokes in inverse proportion?
- Calculate the angle between a pair of consecutive spokes on a wheel with 15 spokes.
- How many spokes would be needed if the angle between a pair of consecutive spokes is 40°?
A school has 8 periods a day each of 45 minutes duration. How long would each period be, if the school has 9 periods a day, assuming the number of school hours to be the same?
Find the constant of variation from the table given below:
| x | 3 | 5 | 7 | 9 |
| y | 12 | 20 | 28 | 36 |
Set up a table and solve the following problems. Use unitary method to verify the answer.
In which of the following table x and y vary inversely:
| x | 9 | 24 | 15 | 3 |
| y | 8 | 3 | 4 | 25 |
Which of the following quantities vary inversely as other?
The number of x men hired to construct a wall and the time y taken to finish the job.
It is known that for a given mass of gas, the volume v varies inversely as the pressure p. Fill in the missing entries in the following table:
| v (in cm3) | ... | 48 | 60 | ... | 100 | ... | 200 |
| p (in atmospheres) | 2 | ... | 3/2 | 1 | ... | 1/2 | ... |
If 36 men can do a piece of work in 25 days, in how many days will 15 men do it?
1200 soldiers in a fort had enough food for 28 days. After 4 days, some soldiers were transferred to another fort and thus the food lasted now for 32 more days. How many soldiers left the fort?
Three spraying machines working together can finish painting a house in 60 minutes. How long will it take for 5 machines of the same capacity to do the same job?
18 men can reap a field in 35 days. For reaping the same field in 15 days, how many men are required?
Raghu has enough money to buy 75 machines worth Rs 200 each. How many machines can he buy if he gets a discount of Rs 50 on each machine?
It takes 60 days for 10 machines to dig a hole. Assuming that all machines work at the same speed, how long will it take 30 machines to dig the same hole?
A toy company requires 36 machines to produce car toys in 54 days. How many machines would be required to produce the same number of car toys in 81 days?
In a school there is 7 periods a day each of 45 minutes duration. How long each period is if the school has 9 periods a day assuming the number of hours to be the same?
Which of the following vary inversely with each other?
If d varies directly as t2, then we can write dt2 = k, where k is some constant.
Write whether the following statement vary directly, vary inversely with each other, or neither of the two.
The number of people working and the time to complete a given work.
If x varies inversely as y and x = 20 when y = 600, find y when x = 400.
Sobi types 108 words in 6 minutes. How many words would she type in half an hour?
Two persons could fit new windows in house in 3 days.
How many persons would be needed to fit the windows in one day?
