Question

LEVEL-2|
15. Seven times a two-digit number is equal to four times the number obtained by reversi
the digits. If the difference between the digits is 3. Find the number.
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Answer 1

Answer:

Step-by-step explanation: let the digit at tens place be x and digit at units place be y

So the number is 10x + y

And reversed number is 10y + x

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

So, y = 2x

We know that y-x = 3

So, 2x - x = 3 ...... As y = 2x...substitute value of y

So, x = 3 and y = 6

Thus the 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 :

2 b - b = 3

b = 3

= > a = 6

Hence number = > 30 + 6

= > 36.