Therefore, the second secretary would take 4 hours while the first secretary would take 4+2 = 6 hours.

Example Two men and 7 children complete a certain piece of work in 4 days. 4 men and 4 children complete the same in only 3 days. Find the number of days required by 1 man or 1 child to complete the same work.

Solution :

Suppose that a man finishes the work in x days and a child in y days.

Then, in 1 day a man does work and

in 1 day a child does work.

Therefore, in 1 day a man and a child together can finish work                    . . . (1)

Now two men and 7 children complete the work in 4 days,

From (1) we get . . . (2)

Again 4 men and 4 children complete it in 3 days

From (1) we get . . . (3)

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Index

9.1 - Definition and Solving Techniques
9.2 - Use of Simultaneous Linear Equations

Chapter 1