Question

The sum of two digit nos is 13. The nos obtained by interchanging the digit is 9 more than the original number. find the original number.​

Answer 1

Answer:

67or 76

Step-by-step explanation:

sum of two digit no. = 13

let ones digit be x

so tens digit be 13-x

two digit no.= 10(13-x)+x

when we interchange the digits

ones digit be 13-x

tens digit be x

so the two digit no. = 10x+ (13-x)

ATQ

10x +(13-x) = 10(13-x)+x+9

10x+13-x=130-10x+x+9

9x+13=139-9x

9x+9x=139-13

18x=126

x=7

so ones digit is 7

tens digit 13-7= 6

so the two digit no is 67 or 76

Answer 2

Answer:

let the two digits be x and y

then x+y=13 and number = 10x + y

after interchanging the digits the number becomes 10y + x

10y + x = 10x + y + 9

9y - 9x = 9

y - x = 1

(x+y) + (y-x) = 13 + 1 = 14

2y =14

y = 7

therefore x = 6

therefore original number = 10×6 + 7 = 67 Ans