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 between the digits is 3, then find the number .

Answer 1

Answer:

36.

Step-by-step explanation:

let the digits be x and y.

y-x = 3

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

=>70x + 7y = 40y+4x

=>33y = 66x

=>y = 2x

//substitute the values

2x - x = 3

x = 3

y = 6

Hence 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.