#### Question

If 15 workers can build a wall in 48 hours, how many workers will be required to do the same work in 30 hours ?

#### Solution

The number of hours required to build a wall is inversely proportional to the number of workers employed.

Let the number of hours be h and the number of workers be w.

Here, h varies inversely as w i.e. \[h \propto \frac{1}{w}\].

∴ \[h = \frac{k}{w}\] , where is k is constant of variation

⇒ h × w = k

When h = 48, w = 15.

∴ k = 48 × 15 = 720

So, the equation of variation is hw = 720.

When h = 30,

30w = 720

⇒ w = \[\frac{720}{30}\] = 24

Thus, the number of workers required to do the same work in 30 hours is 24.

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Solution If 15 Workers Can Build a Wall in 48 Hours, How Many Workers Will Be Required to Do the Same Work in 30 Hours ? Concept: Time, Work, Speed.