The probability that they both have type A: 0.29 x 0.29 = 0.0841
The probability that they both have type A: 0.35 x 0.35 = 0.1225
The probability that they both have type AB: 0.24 x 0.24 = 0.0576
The probability that they both have type O: 0.12 x 0.12 = 0.0144
The probability that they both have the same:
0.0841 + 0.1225 + 0.0576 + 0.0144 = 0.2786