Question

the sum of the digit of a two digit number is 7 if the digits are reserved the new number increased by 3 equals 4 times the original number find the number

Answer 1

Ans.

Let the digits are a and b.
Then the number is (10a + b).

If the digits are reversed, then the new number be (10b + a).

Given that
a + b = 7
or, 2a + 2b = 14 .....(i)

(10b + a) + 3 = 4(10a + b)
or, 39a - 6b = 3
or, 13a - 2b = 1 .....(ii)

Adding (i) and (ii), we get
15a = 15
i.e., a = 1

So, b = 6.

Hence the original number is
10×1 + 6 = 16.

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