Question

7. In
a two digit number the sum of two digits
is 8. If
18 is
added to the number the
digits
are
reversed
find the
number.​

Answer 1

Answer:

35

let number=10X+Y

x+y=8

10X+Y+18=10Y+X

X-Y=-2

X=3

Y=5

number=10×3+5=35

Answer 2

In a two digit number ,

1. The sum of two digits  is 8

2. If  18 is  added to the number the  digits  are  reversed

Let two digit number be " 10x + y "

A/c to condition 1 ,

⇒ x + y = 8 ... (1)

A/c to condition 2 ,

⇒ ( 10 x + y ) + 18 = ( 10y + x )

⇒ 9x - 9y + 18 = 0

⇒ x - y = - 2 ... (2)

Add (1) & (2) ,

⇒ 2x = 6

⇒ x = 3  $\pink{\bigstar}$

Sub. x value in (1) ,

⇒ y = 5  $\orange{\bigstar}$

So , Two digit Number = 10x + y

                                      = 10(3) + 5

                                      = 30 + 5

                                       = 35 $\green{\bigstar}$