Question

Seven times a two digits no. Is equal to 4times the no. Obtained by reversing the order of its digit if the difference of the digit is3determine the no.

Answer 1

Let the tens digit of 2digit number=x
ones digit. =y
the two digit number is 10x+y
acc. to ques.
7(10x+y)=4(10y+x)
70x+7y=40y+4x
70x-4x=40y-7y
66x=33y
y=2x
also y-x=3
2x-x=3
x=3
y=2×3
y=6
the 2digit number is 10x+y
10×3+6
=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.