Question 141

A group of workers can complete a piece of work in 50 days, when they are working individually. On the first day one person works, on the second day another person joins him, on the third day one more person joins them and this process continues till the work is completed. How many approximate days are needed to complete the work ?

Solution

Let a man complete '1' piece of work in a day.

=> Total work = 50 units

Then on 1st day, work done = 1 unit

On 2nd day = 2 units and so on.

Let the whole work will be completed in $$n$$ days.

=> Total work = $$1+2+3+....+n=50$$

=> $$\frac{n(n+1)}{2}=50$$

=> $$n(n+1)=100$$

$$\therefore$$ Number of days $$\approx$$ 10

=> Ans - (C)

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