Question

sum of two digit are 4 the diference obtainded by reversing the digit and by original number by 18 find number​

Answer 1

$\huge \bold{\underline{\sf{\purple{solution-}}}}$

Let the number at tens place be = x

Let the number at unit place be = y

original number = 10x + y

reversing number = 10y + x

Case = 1.

Sum of two digit number = 4

=> x + y = 4 .......(1)

Case = 2.

The difference obtained by reversing the

digit and by original number = 18

=> ( 10y + x) - ( 10x + y) = 18

=> 10y + x - 10x - y = 18

=> 9y - 9x = 18

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

From equation (1) and (2) we get,

=> 2y = 6

=> y = 3

put the value of y = 3 in equation (1) we get,

=> x + 3 = 4

=> x = 1

Therefore,

Therefore,original number = 10x + y = 10(1) + 3 = 13

Answer 2

let the digits are x and y so..

If i write a no. xy then= 10x + y

e.g. 32= 10×3+2

so.. reversing of xy is yx and

yx=10y+x

Now..

A/Q : x-y=3 eq1

10x+ y+ 10y+x = 99 eq 2

so from eq 2

10x+y+10y+x= 99

11x+11y=99

x+y=9 ...... eq 3

Now

from eq 1

we have

x-y=3

x=3+y

substituing value of x in eq 3

x+y=9

3+y+y=9

2y=6

y=3

Substituting value of y in eq1

x-y=3

x-3=3

x=6

so the no. is 36 or 63