"Question 6 A contractor estimates that 3 persons could rewire Jasminder’s house in 4 days. If, he uses 4 persons instead of three, how long should they take to complete the job?
Class 8 Direct and Inverse Proportions Page 214"
Answers
Inverse variation:
Two quantities x and y are said to vary inversely or indirectly if an increase in x causes a decrease in y and a decrease in X causes an increase in y in such a way that xy remains constant.
In other words x and y are said to vary indirectly if x y = k, where K is a positive constant.
In inverse Proportion
xy= k
x=k/y
So we can find value of k from known values, and then use the formula to calculate the unknown values
When two quantities x and y are in direct proportion (or vary directly) they are also written as x∝y.
When two quantities x and y are in inverse proportion (or vary inversely) they are also written as x∝ 1/y
==========================================================
Solution:
Table is in the attachment
Let the number of days required by 4 persons to complete the job be x.
If the number of persons is more, then it will take less time to complete the job.
Hence, the number of days and the number of persons required to complete the job are inversely proportional to each other.
Therefore,
4 × 3 = x × 4
X= (4×3)/4
X= 3
Hence, the number of days required to complete the job is 3 days.
=========================================================
Hope this will help you....
Answer:
Class 8 Direct and Inverse Proportions Page 214"
Step-by-step explanation:
3 days