 ## Book: NCERT - Mathematics

### Chapter: 13. Direct and Inverse Proportions

#### Subject: Maths - Class 8th

##### Q. No. 10 of Exercises 13.2

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10
##### Two persons could fit new windows in a house in 3 days.(i) One of the persons fell ill before the work started. How long would the job take now?(ii) How many persons would be needed to fit the windows in one day?

(i) If the number of persons be more, it will take less time to complete the job. Now, One of the persons fell ill before the work started.

Persons left = 2 – 1 = 1

Therefore,

The number of persons and time required to complete the work are inversely proportional to each other

Therefore,

2 × 3 = 1 × t ( t be the time required to fit the windows by 1 person}

t = 6 days

(ii) If the number of persons be more, it will take less time to complete the job. Now, One of the persons fell ill before the work started.

Therefore,

The number of persons and time required to complete the work are inversely proportional to each other

Let n be the numbers of persons required to complete the work in 1 day.

2 × 3 = 1 × n

n = 6 persons

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