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Set up equation and solve them to find the unknown number in the following case: Munna subtracts thrice the number of notebooks he has from 50, he finds the result to be 8.

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Question

Set up equation and solve them to find the unknown number in the following case:

Munna subtracts thrice the number of notebooks he has from 50, he finds the result to be 8.

Sum
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Solution

Let the number of books be x.

Thrice the number of books = 3x

50 - 3x = 8

-3x = 8 - 50      ...(Transposing 50 to R.H.S.)

-3x = -42

Dividing both sides by -3

`(-3x)/(-3) = (-42)/(-3)`

x = 14

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Chapter 4: Simple Equations - EXERCISE 4.3 [Page 71]

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NCERT Mathematics [English] Class 7
Chapter 4 Simple Equations
EXERCISE 4.3 | Q 1. (e) | Page 71

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