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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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