Four number-pairs are given, out of which three are

Solution

The square of each digit of the first number is added together and then, the resultant is multiplied by 2 to obtain the second number. 468: 232 → [2 × {(4)² + (6)² + (8)² }] = [2 × {16 + 36 + 64}]= [2 × 116] = 232. 552: 108 → [2 × {(5)² + (5)² + (2)² }] = [2 × {25 + 25 + 4}]= [2 × 54] = 108 635: 140 → [2 × {(6)² + (3)² + (5)² }] = [2 × {36 + 9 + 25}] = [2 × 70] = 140 387: 242 → [2 × {(3)² + (8)² + (7)² }] = [2 × {9 + 64 + 49}] = [2 × 122] = 244