Question

Seven times a two digit number is equal to four times the number obtained by reversing the order of its digits. If the difference of the digit is 3 determine the number

Answer 1

Let the ten's digit be x and the one's digit be y.

The original number will be 10x + y and reversed number is 10y + x.

Given 7(10x+y) = 4(10y+x)

          70x + 7y = 40y + 4x

           66x - 33y = 0

           2x - y = 0

            2x = y  ------------- (1)

Given that the difference of the digit is 3.

y - x = 3

2x - x = 3

x = 3

substitute x = 3 in (1), we get

y = 6.


The number is 36.

Answer 2

Answer:

36

Step-by-step explanation:

Let the unit digit be a and tenth unit be b .

So , number = 10 b + a

It's said number is seven times is equal to reversing the order of its digit.

= > 7 ( 10 b + a ) = 4 ( 10 a + b )

= > 70 b + 7 a = 40 a + 4 b

= > 66 b = 33 a

= > a = 2 b ... ( i )

Also given numbers' difference is 3 .

a - b = 3  ( ii )

From ( i ) and ( ii ) we get :

a b - b = 3

b = 3

= > a = 6

Hence number = > 30 + 6

= > 36.