Question

A number consists of two digits and whise sum is 3;if 9isadded to the number ;the digits get interchanged.Then the number is

Answer 1

Hey there !!

Answer: 12 .

Step-by-step explanation:

Let the ten's digit of the required number be x .

And, the unit's digit of the required number be y .

A/Q,

∵ x + y = 3 ............(1) .

Then, the required number = 10x + y .

Number obtained on interchanging its digits = 10y + x .

Now,

⇒ 9 + 10x + y = 10y + x .

⇒ 10x - x + y - 10y = -9 .

⇒ 9x - 9y = -9 .

⇒ 9( x - y ) = -9 .

⇒ x - y = -9/9 .

∵ x - y = -1 ............(2) .

On substracting equation (1) and (2) , we get

x + y = 3 .

x - y = -1 .

-  +       +

________

⇒ 2y = 4 .

⇒ y = 4/2 .

∴ y = 2 .

On putting the value of y in equation (1), we get

∵ x + y = 3 .

⇒ x + 2 = 3 .

⇒ x = 3 - 2 .

∴ x = 1 .

Then , the required number = 10x + y .

= 10 × 1 + 2 .

= 10 + 2 .

= 12 .

Hence, the number is 12 .

THANKS

#BeBrainly .

Answer 2

here is your answer OK ☺☺☺☺☺☺☺☺

☺☺let the two number suppose x and y

Let the digits be x (unit place) and y (tens place). So, the number is 10*y+x.

According to the question,☺☺☺☺

x + y = 9 ___(1)☺☺☺
(10*y + x) - 63 = 10*x + y
10*y - y + x - 10*x = 63
9*y - 9*x = 63
9*(y - x) = 63
y - x = 63/9
y - x = 7 ___(2)
Now, adding (1) and (2), we get☺☺☺☺

(x + y) + (y - x) = 9 + 7
2*y = 16
y = 16/2
y = 8
As, x + y = 9. So,

x = 9 - y = 9 - 8 = 1.
So, the number is 10*y+x = 10*8 + 1 = 81.