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

10 farmers can plough a field in 21 days. Find the number of days reduced if 14 farmers ploughed the same field?

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Question

10 farmers can plough a field in 21 days. Find the number of days reduced if 14 farmers ploughed the same field?

Sum
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Solution

Let the required number of days if 14 farmers ploughed = x

Number of days 21 x
Number of farmers 10 14

As number of farmers increases, number of days decreases.

∴ They are in inverse proportion

x1y1 = x2y2

21 × 10 = x × 14

x = `(21 xx 10)/14`

 x = 15

Initially the farmers worked for 21 days.

Now they worked for 15 days.

∴ The number of days reduced = 21 – 15 = 6 days

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Chapter 4: Direct and Inverse Proportion - Exercise 4.3 [Page 81]

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Samacheer Kalvi Mathematics - Term 1 [English] Class 7 TN Board
Chapter 4 Direct and Inverse Proportion
Exercise 4.3 | Q 11 | Page 81

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