Question

The sum of the digits of a two-digit number is 9. Also, nine times this number is
twice the number obtained by reversing the order of the digits. Find the number,
​

Answer 1

Answer:

Let the unit digit and tens digits of the number be x and y                  

Number = 10y + x                  

Number after reversing the digits = 10x + y    

             

According to the question,                  

⇒  x + y = 9 ... (i)                  

⇒  9(10y + x) = 2(10x + y)                  

⇒  88y - 11x = 0                  

⇒ -x + 8y =0 ... (ii)                  

Adding equation (i) and (ii), we get                  

⇒  9y = 9                  

⇒  y = 1 ... (iii)                  

Putting the value in equation (i), we get                  

⇒  x = 8                  

Hence, the number is 10y + x = 10 × 1 + 8 = 18.

Answer 2

let ,no be 10 x + y

on reversing 10y+x

here x+y=9

ATQ,

2(10x+y)= 9(10y+x)

now solve it you will get you answer.

regards