Question

A number consists of two digits and sum of boths digits is 12. the digits at ones place is three times the digits at tens place. find the number.​

Answer 1

✯ The number = 39✯

Step-by-step explanation:

Given:

• A number consists of two digits and sum of both digits is 12.
• The digit at one's place is 3 times the digit at ten's place.

To find:

• The number.

Solution:

Let the ten's digit of the number be x and the unit's digit of the number be y.

Then,

• The number = 10x+y

✯ ${\underline{\sf{According\:to\:the\:1st\: condition:-}}}$

• A number consists of two digits and sum of both digits is 12.

$\implies$ x + y = 12............(i)

✯ ${\underline{\sf{According\:to\:the\:2nd\: condition:-}}}$

• The digit at one's place is 3 times the digit at ten's place.

$\implies$ y = 3x..............(ii)

†Now take eq(i) and put the value of y from eq(ii).

$\implies$ x +3x = 12

$\implies$ 4x = 12

$\implies$ x = 12/4

$\implies$ x = 3

†Now put x = 3 in eq(ii) for getting the value of y.

$\implies$ y=3×3

$\implies$ y=9

Therefore,

• The number = 10×3 +9 = 39

__________________

Answer 2

Given:

• The sum of the digits of a two digits number is 12
• Digit at once place is three times the digit at tens plce.

Find:

• Actual number

Solution:

Let, the ten's digit of the number be x

and the unit's digit be y

So, the Actual number ➨ 10x + y

Now,

$\gray{\mathbb{ACCORDING \: TO \: QUESTION}}$

$\sf \to x + y = 12.....(1)$

$\sf \to y = 3x.....(2)$

Taking eq(2)

$\sf \to x + y = 12$

$\sf \implies x = 12 - y$

Now, put this value of x in eq(1)

$\sf \to y = 3x$

$\sf \implies y = 3(12 - y)$

$\sf \implies y = 36 - 3y$

$\sf \implies y + 3y = 36$

$\sf \implies 4y = 36$

$\sf \implies y = \cancel{\dfrac{36}{4} } = 9$

$\sf \implies y = 9$

So, y = 9

________________

Put value of y in the eq(2)

$\sf \to x + y = 12$

$\sf \implies x + 9 = 12$

$\sf \implies x = 12 - 9$

$\sf \implies x = 3$

So, x = 3

________________

Actual Number:

$\sf \to 10x + y$

$\sf \to 10(3) + (9)$

$\sf \to 30 + 9$

$\sf \to 39$

Hence, the actual number will be 39