Question

The sum of the digits of a two-digit number is 13. If 9 is added to the number, the digits are reversed. Then the original number is

(I want the answer in one variable)

Answer 1

Step-by-step explanation:

let,

no.=10x+y

so,

10x+y+9=10y+x

10x-x+y-10y= -9

9x-9y= -9

9(x-y)= -9

x-y= -9/9

x-y= -1

it is given that,

x+y=13 so,

x+y+x-y=13+(-1)

2x=13-1

2x=12

x=12/2

x=6

and x+y=13

6+y=13

y=13-6=7

so; number is 10x+y=10×6+7=60+7=67

Answer 2

Answer:

67

Step-by-step explanation:

Let the number be written as = 10x + y

sum of two digit number is =

=> x + y = 13 ....... (1)

9 is added to the number

=> 10x + y + 9 = 10y + x

=> 9x - 9y = -9

=> x - y = -1...... (2)

from equation (1) and (2) we get

=> 2x = 12

=> x = 6

put x = 6 in equation (1)

=> 6 + y = 13

=> y = 7

the original number is = 10x + y

=> 10 (6) + 7

=> 67 = ANSWER