Question

Ich a + b + c
The sum of digits of a two digit number is 5. If the number obtained by reversing the digits is 9 more than the
number, find the number.
In a 3-digit number, hundred's digit is twice the unit's digit and the ten's digit is thrice the unit's digit. If the sum
of the digits is 12, find the number.​

Answer 1

Answer:

∴ The original number is 10x+y=10(2)+3=20+3=23.

Step-by-step explanation:

Let the tens digit =x

Let the units digit =y

The sum of digits of a two digit number is 5, so x+y=5

When the digits are reversed, the number is 9 more than the original

since x is your tens digits, its value is 10x.

So, yo have the value of your original number 10x+y.

Now, reverse the digits the number =10y+x

So, equation formed =10y+x=(10x+y)=9

⇒10y−y=10x−x+9

⇒9y=9x+9

⇒9y−9x=9

⇒9(y−x)=9

⇒y−x=9/9=1

y−x=1

y+x=5

_________

2y=6

⇒y=6/2

⇒y=3

Put y in y−x=1

3−x=1

−x=1−3

x=2