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The ratio of a two-digit natural number to a number formed by reversing its digits is 4: 7. The number of such pairs is
  • a)
    5
  • b)
    4
  • c)
    3
  • d)
    2
Correct answer is option 'C'. Can you explain this answer?
Most Upvoted Answer
The ratio of a two-digit natural number to a number formed by reversin...
Explanation:

Let the two-digit number be "10x + y".

When the digits are reversed, the number becomes "10y + x".

Given, (10x + y)/(10y + x) = 4/7

Cross-multiplying, we get 70x + 7y = 40y + 4x

Simplifying, we get 66x = 33y

Therefore, x = y * 2

Since x and y are digits, the only possible values for y are 1, 2, 3, 4, and 5.

If y = 1, then x = 2, which gives the number 12.

If y = 2, then x = 4, which gives the number 24.

If y = 3, then x = 6, which gives the number 36.

If y = 4, then x = 8, which gives the number 48.

If y = 5, then x = 10, which gives the number 50.

Therefore, there are only 3 pairs of two-digit numbers that satisfy the given condition.

Hence, option C is the correct answer.
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The ratio of a two-digit natural number to a number formed by reversin...
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