Question

Seven times a 2 digit number is equel to 4 times the number obtained by reversing the order of digit and the sum of digits of the number is 3.find the number

Answer 1

Answer:

X=1

Y=2

Step-by-step explanation:

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

70x+7y=40y+4x

70x-4x=40y-7y

66x=33y

66x-33y=0

Divide by 11

6x-3y=0

Divide by 3

2x-y=0

Y=2x...1

Substitute in x+y=3

X+2x=3

3x=3

X=1

Y=2

Answer 2

Answer:

12

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' sum is 3 .

a + b = 3  ( ii )

From ( i ) and ( ii ) we get :

2 b + b = 3

b = 1

= > a = 2

Hence number = >  10 + 2

= > 12.