Let the first digit be t
Therefore the second digit is t-4. The number is 10 times the first digit plus the second digit The number = 10t + t-4 = 11t - 4 Digits' sum = t + t-4 = 2t - 4
11t - 4 ——————— = 7 2t - 4 Multiply both sides by (2t - 4) 11t - 4 = 7(2t - 4) 11t - 4 = 14t - 28 -3t = -24 t = 8 The second digit is t-4 = 8-4 = 4 So the number is 84. Edwin