(119) 1

Part of 1986 Tournament Of Towns

Problems(1)

TOT 119 1986 Autumn J1 find 2-digit numbers , one is twice as big as the other

Source:

We are given two two-digit numbers ,

x

y

. It is known that

x

is twice as big as

y

. One of the digits of

y

is the sum, while the other digit of

y

is the difference, of the digits of

x

. Find the values of

x

y

, proving that there are no others.

number theoryDigits2-digitSumDifference