Question

In a two - digit number, unit's digit is twice the ten's digit. If sum of the digits is
added to the whole number, the result is equal to 30. Find the number.

please answer this question with a proper solution.​

Answer 1

Answer:

In a number of two digits the unit's digit is twice the tens digit If 36 is added to the number the digits are reversed find the number

Answer: If 36 be added to the number, the digits are reversed and the unit's digit is 2 times the ten's digit, then the number is option (c): 48.

Answer 2

Answer:

• Number is 39.6

Given :

• In a two - digit number unit's digit is twice the ten's digit
• The sum of the digits is added to the whole number the result is equal to 30

To find :

• The number

Solution :

• Let the unit's digit be y
• Let the Ten's digit be x

Then, (10x + y)

Given that , in a two digit number unit's digit is twice the ten's digit so,

• y = 2x

And also Given that,the sum of digits is added to the whole number the result is equal to 30 then,

• [10x + y] + 30 = 10x + y

》10x + y + 30 = 10x + y

》9x - 9y + 30 = 0

》9x - 9y + 30 = 0 is eq (1)

Now substituting y = 2x in eq (1) we get,

》9x - 9(2) = -30

》9x - 18 = -30

》9x = - 30

》x = 30/9

》x = 3.3

Now,

• y = 2x = 2(3.3) = 6.6

Then, number is ,

• 10 × 3.3 + 6.6 = 33 + 6.6 = 39.6

Hence , number is 39.6