English
Tamil Nadu Board of Secondary EducationSSLC (English Medium) Class 7

6 pumps are required to fill a water sump in 1 hr 30 minutes. What will be the time taken to fill the sump if one pump is switched off?

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Question

6 pumps are required to fill a water sump in 1 hr 30 minutes. What will be the time taken to fill the sump if one pump is switched off?

Sum
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Solution

Let x be the required time taken

Time taken in minutes 1 hr. 30 m = 90 m x
Number of pumps 6 6 − 1 = 5

As the number of pumps increases the time taken to fill the sump will be less 

∴ They are in inverse proportion

x1y1 = x2y2

90 × 6 = x × 5

     1
`"60)"overline108("`
       60
       48

x = `(90 xx 6)/5`

= 108 minutes

= `108/60`

= 1 hr. 48 min

Time taken in minutes 1 hr. 48 m

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Chapter 4: Direct and Inverse Proportion - Exercise 4.2 [Page 80]

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Samacheer Kalvi Mathematics - Term 1 [English] Class 7 TN Board
Chapter 4 Direct and Inverse Proportion
Exercise 4.2 | Q 2 | Page 80

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