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  1. A number consists of two digits such that the digit in the ten’s place is less by 2 than the digit in the unit’s place. Three times the number added to 6/7 times the number obtained by reversing the digits equals 108. The sum of digits in the number is :
    1. 8
    2. 9
    3. 6
    4. 7
Correct Option: D

Let the unit’s digit be x.
∴  Ten’s digit = x – 2
∴  Number = 10 (x – 2) + x
= 10x – 20 + x = 11x – 20
New number obtained after reversing the digits
= 10x + x – 2 = 11x – 2
According to the question

3(11x − 20) +
6
(11x – 2) = 108
7

⇒ (11x − 20) +
2
(11x – 2) = 36
7

⇒  77x – 140 + 22x – 4 = 252
⇒  99x = 252 + 144
⇒  x =
396
= 4
99

∴  Number = 11x – 20
= 11 × 4 – 20 = 24
∴  Sum of digits = 2 + 4 = 6



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