Question

He difference between a two digit number and its reverse is 36. what could be the difference between the two digits of the number a)4 b)9 c)7 d)6

Answer 1

xy - yx = 36

xy can be written as 10x + y and yx can be written as 10y + x

so substituting we get

10x + y - 10y -x = 36

9x - 9y = 36

x - y = 4