Question

seven times a two digit number is equal to four times the number obtained by reversing the order of its digit if the difference of the digit is 3 find the number​

Answer 1

$\mathfrak{\large{\underline{\underline{Solution:}}}}$

• Let ten digit = $x$

• Then, unit digit = $y$

∴ The number will be $= 10x + y$

On reversing the digits, we have:

$= 10y + x$

Now, ATQ

or, $7(10x + y) = 4(10y + x)$

or, $70x + 7y = 40y + 4x$

or, $66x = 33y$

$2x = y \: \: \: \: \: \: .........(1)$

It is said that the difference between them is 3.

So, (Note:— Since x is less than y)

$y - x = 3 \: \: \: .........(2)$

Putting the value of x

or, $2x - x = 3$

or, $x = 3$

$y = 2 \times 3 = 6$

Hence, the original number is 36 and the reversed number is 63.

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.