Question

A number consists of two digits whose sum is 9. If 27 is subtracted from the number,its digit are reversed.find the number

Answer 1

Answer:

The number is 63.

Step-by-step explanation:

Let the two digits be a and b. Let a be the ten's digit and b be the units digit.

The number will be a x 10 + b and we know that a + b= 9.

a + b=9 is the first equation.

If a x 10 + b ‐ 27= b x 10 + a because b will now be the ten's digit and a will be the unit's digit.

If a x 10 + b ‐ 27= b x 10 +a

then 10a + b ‐ 27= 10b + a

10a + b ‐ 10b ‐ a= 27

9a ‐ 9b=27

9(a ‐ b)=27

a ‐ b=27/9

a ‐ b=3 is the second equation.

Adding the first and second equation we get,

a+b=9

a ‐ b=3

b and  ‐b will be cut so we'll get 2a=12

Hence, a=12/2= 6

Substituting the value of a in first equation we get,

a+b=9

6+b=9

b=9-6

b=3

The number is a x 10+b= 6x10+3 = 60+3 = 63

Hope this helped you :)