Question

the sum of the digits of a two digit number is 12 if the digits are reversed the new number become 4/7 times the original number find the original number

Answer 1

this is the answer to your question

Answer 2

Let the number be xy . it can also be expressed as 10x+y . x+y=12 . when reversed it becomes y-x and can be expressed as 10y+x. 10y+x=4/7(10x+y) =>
7(10y+x)=4(10x+y)=> 70y+7x=40x+4y=>70y-4y=40x-7x=>66y=33x=> 2y=x
2y+y=12=> 3y=12=> y=4. x=2y=2(4)=8. So the original number is 8(10)+4=84.