Question

The sum of the digits of two digits numbers together with 7 is 3 times the digits in its tens place. if 8 be subtracted from the number the digits of the number interchange their positions .find the number ? What is the ans... Can anyone ans this one

Answer 1

Let the two digits be a,ba,b then the number is 10a+b10a+b.

The sum of the digits is eleven: a+b=11a+b=11

Reversing the digits gives the number 10b+a10b+a which is nine larger than the original number, so:

     (10b+a)=(10a+b)+9⇒b=a+1(10b+a)=(10a+b)+9⇒b=a+1

Substituting for bb in the sum of the digits we get:

     2a+1=11⇒a=5,b=62a+1=11⇒a=5,b=6

Hence the number is 5656.