Find the greatest number that divides 130, 305 and 245 leaving remainders 6, 9 and 17, respectively?

Given that,
x = 130, y = 305, z = 245
a = 6, b = 9, c = 17
According to the formula,
Required number = HCF of [(130 - 6), (305 - 9), (245 - 17)]
= HCF of 124, 296, 228 = 4.