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A Positive Number is 5 Times Another Number. If 21 is Added to Both the Numbers, Then One of the New Numbers Becomes Twice the Other New Number. What Are the Numbers? - CBSE Class 8 - Mathematics

ConceptSome More Applications

Question

A positive number is 5 times another number. If 21 is added to both the numbers, then one of the new numbers becomes twice the other new number. What are the numbers?

Solution

Let the numbers be x and 5x. According to the question,

21 + 5x = 2(x + 21)

21 + 5x = 2x + 42

Transposing 2x to L.H.S and 21 to R.H.S, we obtain

5x − 2x = 42 − 21

3x = 21

Dividing both sides by 3, we obtain

x = 7

5x = 5 × 7 = 35

Hence, the numbers are 7 and 35 respectively.

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APPEARS IN

NCERT Solution for Mathematics Textbook for Class 8 (2018 to Current)
Chapter 2: Linear Equations in One Variable
Ex. 2.40 | Q: 2 | Page no. 31
Solution A Positive Number is 5 Times Another Number. If 21 is Added to Both the Numbers, Then One of the New Numbers Becomes Twice the Other New Number. What Are the Numbers? Concept: Some More Applications.
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