Question

A two digit number is such that, the sum of its digits is 13. When the digits are interchanged, the original number is increased by 9. Find the original number.

Answer 1

for the original number:
unit digit --- x
tens digit --- y
the original number is 10y+x

reversed number:
unit digit --- y
tens digit --- x
reversed number is 10x + y

10y+x - (10x+y) = 9
9y - 9x = 9
x - y = 1 , but
x + y = 13
add them:
2x = 14
So x = 7 and y = 6
The original number is 67

Answer 2

Why is x not a tens digit and yet it is in the tens alignment

Answer 3

Wrong alignment, the original number is increased by 9←means you take the reversed number which is 10x+y-(10y+x)=9 instead of your computation, check it

Answer 4

Good ans thank you

Answer 5

What if the number is 19 which will be reversed number?

Answer 6

I don't get where this 10 is from??

Answer 7

Where has 10 come from

Answer 8

Where does this 10 come from

Answer 9

XY x=ones y=tens 10y+x reverse 10x+y 10y+x-(10x+y)=9. 9y-9x=9. x-y=1. x+y=13 2x=14 x =7,y=6 answ=67

Answer 10

How did you get the 6?

Answer 11

You have complicated on the place where you assign the place value

Answer 12

Do not understand still need help