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 digits is 3, determine the
number.

Answer 1

Let the tens place digit be a

And Unit place digit be b

According to first condition,

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

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

=> 66a = 33b

=> 2a = b

=> b = 2a ---------(1)

Now,

According to second condition,

b - a = 3

=> 2a - a = 3

=> a = 3

On Substituting the value of a in equation (1), we get


b = 2× 3 = 6

Required number = 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.