Question

In a two digit number,the number at the units place is equal to the number at tens place. If 18 is added to the number the digits get interchanged.Find the number

Answer 1

heya!!!

GENERAL CONCEPT.

ANY TWO DIGIT NUMBER ( yx)

CAN BE REPRESENT LIKE THIS

10x + y

EXP:-

Let the number at units place be y and let the number at tens place be x

ACCORDING TO THE QUESTION!

x² = y ..... equation 1

10y + x = 18 + 10x + y

9y - 9x = 18

x² - x = 2 ..... equation 2

Now, put value of x in equation 2

x² - x = 2

x² - 2x + x - 2 = 0

x ( x - 2 ) + 1 ( x - 2 ) = 0

x = -1 or x = 2

For x = -1 y = 1

For x = 2 y = 4

so, the no. is

24