Given PQR - QPR = 90
When the difference is 90 the numbers will be 101 - 011, 216 - 126, 879 - 789.........
In each three digit numbers Q is one less than P
∴ There are 9 possible values (1,0) (2,1) (3,2) (4,3) (5,4) (6,5) (7,8) (8,7) (9,8).
Given PQR - QPR = 90
When the difference is 90 the numbers will be 101 - 011, 216 - 126, 879 - 789.........
In each three digit numbers Q is one less than P
∴ There are 9 possible values (1,0) (2,1) (3,2) (4,3) (5,4) (6,5) (7,8) (8,7) (9,8).